Goniatites Zone (middle Mississippian) ammonoids of the Antler Foreland Basin (Nevada, Utah)

DIETER KORN & ALAN L. TITUS

The ammonoid faunas from the Goniatites Zone (Late Viséan; Mississippian) of the Camp Canyon Member (Chainman Formation) are described for the first time. The assemblage shows close relationships to time equivalent occurrences in Alaska and the American Midcontinent, but differs markedly from occurrences in Europe, North Africa, and the South Urals. Seven successive ammonoid biozones are proposed for this interval in North America, in ascending or- der: (1) Calygirtyoceras confusionense Ammonoid Biozone, (2) Calygirtyoceras arcticum Ammonoid Biozone, (3) Girtyoceras primum Ammonoid Biozone, (4) Girtyoceras gordoni Ammonoid Biozone, (5) Goniatites deceptus Ammonoid Biozone, (6) Goniatites eganensis Ammonoid Biozone, and (7) Goniatites multiliratus Ammonoid Biozone. The following ammonoid species are revised or newly described: Bollandoceras occidentale sp. nov., Entogonites burbankensis sp. nov., Entogonites borealis (Gordon, 1957), Entogonites acus sp. nov., Calygirtyoceras confusionense sp. nov., Calygirtyoceras arcticum Gordon, 1957, Girtyoceras primum sp. nov., Girtyoceras gordoni sp. nov., Girtyoceras hamiltonense sp. nov., Dimorphoceras worki sp. nov., Dimorphoceras rileyi sp. nov., Metadimorphoceras mangeri sp. nov., Metadimorphoceras richardsi sp. nov., Kazakhoceras bylundi sp. nov., Goniatites americanus Gordon, 1971, Goniatites deceptus sp. nov., Goniatites eganensis sp. nov., Goniatites sowerbyi sp. nov., and Praedaraelites loeblichi (Miller & Furnish, 1940). • Key words: Ammonoidea, Carboniferous, Mississippian, Viséan, Nevada, Utah, palaeobiogeography, biostratigraphy, Chainman Formation.

KORN,D.&TITUS, A.L. 2011. Goniatites Zone (middle Mississippian) ammonoids of the Antler Foreland Basin (Ne- vada, Utah). Bulletin of Geosciences 86(1), 107–196 (60 figures, 37 tables, appendix). Czech Geological Survey, Prague. ISSN 1214-1119. Manuscript received November 8, 2010; accepted in revised form January 24, 2011; published online March 8, 2011; issued March 14, 2011.

Dieter Korn, Museum für Naturkunde, Leibniz Institute at the Humboldt University Berlin, Invalidenstraße 43, 10115 Berlin, Germany; [email protected] • Alan L. Titus, Grand Staircase-Escalante National Monument, Kanab, Utah 84741; [email protected]

Goniatites de Haan, 1825 has the distinction of being one al. 2006), the South Urals (Bogoslovskaya 1966, Ruzhen- of the first named Carboniferous ammonoid genera. Even cev 1966), Novaya Zemlya (Kusina 1987, Kusina & Yats- though many species formerly assigned to the genus are kov 1999), Xinjiang (Liang & Wang 1991), Alaska (Gor- now referred to other genera like Arnsbergites, Lusitanoce- don 1957), and the United States Midcontinent (e.g. Girty ras, Paraglyphioceras, and Dombarites (Korn 1988), it 1909, 1911; Gordon 1962, 1965; Drahovzal 1972; Drahov- still has a 6 Ma chronostratigraphic range (Korn & Kauf- zal & Quinn 1972; Saunders et al. 1977). The stratigraphic mann 2009) and a nearly global distribution. The genus occurrence of this distinctive taxon was even considered ranges through a large part of the late Viséan (Asbian and evolutionarily significant enough to warrant Ramsbottom early Brigantian equivalent) and has been reported from & Saunders (1985) to establish its range as a formal Early the European North Variscan basins such as the British Carboniferous genus zone. Isles (e.g. Bisat 1924, 1934, 1952; Moore 1936, 1946, Goniatites also occurs in strata of North America’s 1952, 1958; Hodson & Moore 1959), the Rhenish Mounta- Antler Foreland Basin (Webster et al. 1984, Huh 1968), ins (e.g. Brüning 1923; Schmidt 1925; Nicolaus 1963; which extends over 2,500 km from Canada to south-east- Korn 1988, 1990, 1997a), the Ardennes (e.g. de Koninck ern California (Fig. 1) and resulted from subsidence caused 1880, Delépine 1940), the South Portuguese Zone (Korn by the formation of the Antler Orogenic Highland in the 1997b, Korn & Horn 1997), the Moroccan Meseta (Delé- Late Devonian and Mississippian (Eisbacher 1983). Antler pine 1941, Korn & Ebbighausen 2008), South Variscan ba- Foreland Basin strata is Late Devonian to early Pennsylva- sins such as the Cantabrian Mountains (Kullmann 1961), nian in age and locally richly fossiliferous, with ammonoids the Anti-Atlas of Morocco (Korn et al. 2005, 2007; Klug et occurring through most of the Early Carboniferous part of

DOI 10.3140/bull.geosci.1242 107 Bulletin of Geosciences • Vol. 86, 1, 2011

Figure 1. Palaeogeographic map of the eastern United States for the late Missis- sippian (modified after an image by Ron Blakey; http://jan.ucc.nau.edu/~rcb7/). Abbreviations: PF – Proximal Foredeep; MF – Medial Foredeep; DF – Distal Foredeep; SDM – Sierra Diablo Moun- tains; LU – Llano Uplift; AM – Ar- buckle Mountains; OP – Ozark Plateau.

Figure 2. Map of east-central Nevada showing ammonoid localities. Abbrevi- ations: DW – Duckwater Hills; CC – Cathedral Canyon; HC – Hamilton Can- yon; TSC – Trough Springs Canyon; RS – Rosebud Spring; PEC – Pony Ex- press Canyon. Dark grey shading shows Mississippian outcrops.

the sequence (Gordon et al. 1957; Gordon 1970, 1986; ingly, the only previously published systematic treatments Webster et al. 1984; Petersen et al. 2000; Titus 2000; Work of Goniatites Zone (sensu Ramsbottom & Saunders 1985) et al. 2000; Titus & Manger 2001). Late Viséan (Asbian ammonoids from the Antler Foreland Basin are two brief and Brigantian of the British stratigraphic scheme) studies of three taxa (Miller et al. 1949, Gordon 1971). ammonoids are particularly common in the shale and car- In 1992, ALT began measuring sections and collecting bonate sequences of eastern Nevada and western Utah, and ammonoids from within the Antler Foreland Basin in east- to a lesser extent of southern Idaho (Huh 1968). Surpris- ern Nevada and western Utah (Figs 2, 3) for his dissertation

108 Dieter Korn & Alan L. Titus • Goniatites Zone (middle Mississippian) ammonoids, Nevada and Utah

Figure 3. Map of west-central Utah showing ammonoid localities. Abbrevia- tions: NR – Needle Range; SBH – South Burbank Hills; JW – Jensen Wash; CMW – Conger Mountain West; CME – Conger Mountain East; MC1–MC3 – Middle Confusion Range 1–3; BSH – Bishop Springs Dome; GM – Granite Mountain. Dark grey shading shows Mississippian outcrops.

research. Only late early Serpukhovian (Arnsbergian Previous work Stage) material was treated systematically in this work (Ti- tus 2000), but a large number of early Serpukhovian Antler Foreland Basin (Pendleian) and late Viséan ammonoid specimens were also assembled. The new material led ALT to the conclu- Inexplicably, nearly all material in early collections from sion that the Antler Foreland Basin’s Late Viséan the study area is Serpukhovian in age (e.g. Hall & Whitfield ammonoid record was much more continuous, diverse and 1877; Miller & Furnish 1940; Youngquist 1949a, 1949b). significant than reported in its most recently published re- The region’s first description of ammonoids from the Go- view by Webster et al. (1984). niatites Zone was by Miller et al. (1949; plate 99, Over the course of the next 15 years, ALT continued to figs 7–10), who illustrated specimens of Goniatites and collect stratigraphically located Late Viséan ammonoid Girtyoceras collected from the White Pine Range area of material from Nevada and Utah, which forms the bulk of east-central Nevada. We could not relocate the locality, this study. Subsequent collections made by ALT with the and the specimens are immature, but we can still make con- assistance of Nicholas J. Riley, Barry Richards, and DK fident species level assignments: ‘Goniatites choctawensis have greatly refined the biostratigraphic resolution of the Shumard, 1863’ (= Goniatites eganensis sp. nov.), succession around the Asbian–Brigantian stage boundary ‘Girtyoceras aff. G. meslerianum (Girty, 1909)’ (= Girtyo- and confirmed the region contains a remarkable, previ- ceras hamiltonense sp. nov.). ously undocumented high-resolution record of the evolu- The first substantial collections of Asbian and early tion of Goniatites and other contemporaneous ammonoid Brigantian ammonoids from the region were made in the taxa. This systematic review of newly collected material late 1950s by mapping teams from the United States Geo- establishes a high-resolution Asbian–early Brigantian logical Survey working in west-central Utah. Although ammonoid biostratigraphic zonation for the Antler Fore- biostratigraphic analyses of these collections were made by land Basin and documents ammonoid diversity for that Mackenzie Gordon Jr. (Gordon et al. 1957, Gordon 1970, time. Our work has also shown that recent advances in the Webster et al. 1984), most of this material has only been re- phylogeny and biostratigraphy of Viséan ammonoids ported through faunal lists. The single systematic paper (Korn 1988, 1996), as well as our new data from the Ant- that resulted from these collections (Gordon 1971) named ler Foreland Basin region, has necessitated restudy of Goniatites americanus using specimens collected at Gran- even seemingly well-known North American assem- ite Mountain, Juab County, Utah as the primary types. blages. The most recent published work on these assemblages

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(Webster et al. 1984) lists, in ascending order, the follow- taxa from the Kuna Formation that we consider contempo- ing taxa (with our revisions): raneous with the assemblages in this study: ‘Bollandites Goniatites americanus Zone: ‘Goniatites americanus bowsheri Gordon, 1957’ (= Bollandites bowsheri Gordon, Gordon, 1971’ (= Goniatites americanus Gordon, 1971), 1957), ‘Beyrichoceras micronotum (Phillips, 1836)’ [= Bol- ‘Girtyoceras arcticum Gordon, 1957’ [= Calygirtyoceras landoceras cf. micronotum (Phillips, 1836)], ‘Goniatites arcticum (Gordon, 1957)], ‘Girtyoceras n. sp. A’ (= Girtyo- crenistria Phillips, 1836’ (= Goniatites americanus Gor- ceras primum sp. nov.), ‘Entogonites borealis Gordon, don, 1971), ‘Girtyoceras arcticum Gordon, 1957’ [= Caly- 1957’ [= Entogonites borealis Gordon, 1957 (part)], ‘Di- girtyoceras arcticum (Gordon, 1957)], ‘Girtyoceras endi- morphoceras n. sp.’ (= Dimorphoceras sp.), ‘Prolecanites cottense Gordon, 1957’ (= Girtyoceras endicottense sp.’ (= ? Praedaraelites sp.). Gordon, 1957), ‘Dimorphoceras algens Gordon, 1957’ Goniatites multiliratus Zone: ‘Goniatites multiliratus (= Dimorphoceras algens Gordon, 1957), ‘Entogonites bo- Gordon, 1962’ (= Goniatites deceptus sp. nov.), ‘Girtyo- realis Gordon, 1957’ (= Entogonites borealis Gordon, ceras meslerianum (Girty, 1909)’ (= Girtyoceras hamil- 1957). tonense sp. nov.). Two other taxa named in that paper, Sudeticeras Unfortunately, Mackenzie Gordon Jr. died in 1992 be- alaskae Gordon, 1957 (actually Wiedeyoceras sp.) and fore he was able to publish an intended monographic treat- Eothalassoceras aurorale Gordon, 1957 (actually Eotha- ment of this material. lassoceras inexpectans Miller & Owen, 1937), are based Walter Sadlick (1960, 1965, 1995) also published on Pennsylvanian specimens from the Seminole Formation ammonoid species lists that include Viséan taxa (with iden- of eastern Oklahoma that were erroneously mixed with the tifications made by Mackenzie Gordon Jr.) based on mate- Alaskan Viséan material (Gordon 1965). It is important to rial he collected during his dissertation research on note that all of the material from the Kiruktagiak locality Chainman stratigraphy. This author reports the following including the type specimens was collected without regard Asbian–early Brigantian taxa in his dissertation: to precise stratigraphic control and came from a 13 metres ‘Goniatites crenistria Zone (equals G. americanus thick interval of concretionary shale. Given the mix of Zone of Webster et al. 1984): ‘Goniatites crenistria Phil- morphologies in the type suites for Entogonites borealis lips, 1836’ (= Goniatites americanus Gordon, 1971), and Calygirtyoceras arcticum, as well as their association ‘Girtyoceras sp.’ [= Calygirtyoceras arcticum (Gordon, with true Girtyoceras (G. endicottense), we believe most of 1957)]. these taxa are probably based on stratigraphically mixed Goniatites multiliratus Zone: ‘Goniatites multiliratus samples coming from at least two distinct Asbian zones. Gordon, 1962’ (= Goniatites deceptus sp. nov.). Additional sampling is needed before this issue can be re- Huh (1968) reported that abundant, but poorly pre- solved. served Goniatites occur in the Scott Peak Formation, north Sellers & Furnish (1960) described specimens of of the Snake River Plain in Idaho. This is one of the only Goniatites crenistria Phillips, 1836, collected from the other areas in the Antler Foreland Basin known to yield headwaters area of the Peel River, Yukon (north-western three-dimensional Goniatites Zone ammonoids outside of Canada), from an unnamed dark silty shale unit that is Nevada and Utah. However, this material remains unpub- probably correlative with the Kuna Formation. The speci- lished and we have not personally examined specimens mens possess distinctive V-shaped ventral lobes with shal- from the locality. low medial saddles and crenistriate ornament and we tenta- tively refer them to Goniatites americanus Gordon 1971, of Asbian (early Chesterian) age. Northern Alaska/North-western Canada

Late Viséan ammonoids were first reported from Alaska by Illinois Basin Gordon (1957). In this important paper, several new taxa were named from collections made in the eastern DeLong Asbian ammonoids have long been known to occur on the Mountains, Ipnavik River Basin, Etivluk River Basin, Ki- western and north-eastern margin of the Illinois Basin ruktagiak River Basin, and Anaktuvuk River Basin areas (Collinson 1955, Knapp 1965). A single specimen collec- from the Black Shale Member of the Alapah Limestone, ted from the Monroe, Illinois area served as the holotype now assigned to the Kuna Formation (Mull et al. 1982). for Goniatites monroensis (Worthen, 1890), which was lat- The most extensive and important collections are from the er, redescribed by Collinson (1955) and referred to Prole- Kiruktagiak River Basin localities from which the types of canites. The west side of Greencastle, Indiana also yields Dimorphoceras algens Gordon 1957, Girtyoceras arcti- an abundant, well-preserved Goniatites Zone ammonoid cum Gordon 1957, and Entogonites borealis Gordon 1957 fauna (Miller & Gurley 1896), from which they named were obtained. In summary, Gordon (1957) listed seven the species Goniatites greencastlensis. Collinson (1955)

110 Dieter Korn & Alan L. Titus • Goniatites Zone (middle Mississippian) ammonoids, Nevada and Utah further clarified that the widely separated Monroe and Green- 1863’, ‘Goniatites sp.’, “Girtyoceras sp. cf. G. mesleria- castle localities are both in the basal beds of the Ste. Gene- num (Girty, 1909)’, ‘Neoglyphioceras cloudi (Miller & vieve Formation (earliest Chesterian) and contain essenti- Youngquist, 1948)’, ‘Neoglyphioceras sp.’, and “Lyrogo- ally the same assemblage. Knapp (1965) reviewed the niatites sp. cf. L. newsomi (Smith, 1903)’ based on collecti- Greencastle assemblage, added Bollandites phillipsi (Bi- ons made by J.B. Knight, A.K. Miller, and W.M. Furnish in sat, 1934) and Prolecanites serpentinus (Phillips, 1836) to the 1930s and 1940s at the Figure 2 Ranch. Even though we the species list, and concluded that Goniatites greencas- have not examined them, we believe these collections are tlensis, owing to its widely umbilicate juvenile stage and stratigraphically mixed, with Goniatites “crenistria” and narrow ventral lobe of the suture, doesn’t belong in Gonia- Girtyoceras sp. cf. G. meslerianum coming from the upper tites. We currently see no reason why Goniatites greencas- portion of the Goniatites Zone and the remainder from tlensis Miller & Gurley, 1896 should not be referred to the higher in the section. There is only one known locality that genus Bollandites, even though it is one of the widest shel- produces prolific Brigantian ammonoid material at the Fi- led species in the generic complex. gure 2 Ranch and this was revisited in 2000 by ALT. Based Recent collecting at this locality by David M. Work and on these collections, King’s Goniatites crenistria Phillips, ALT has secured the previously reported Bollandites 1836 is probably G. eganensis sp. nov. and Girtyoceras sp. greencastlensis (Miller & Gurley, 1896), Bollandites cf. G. meslerianum (Girty, 1909) is Girtyoceras welleri phillipsi (Bisat, 1934) and Prolecanites americanus Miller Gordon, 1965. & Garner, 1953 (P. serpentinus of Knapp 1965), along with a crenistriate variety of Goniatites (cf. G. americanus Llano Uplift. – Barnett Shale outcrops in the Llano Uplift Gordon, 1971) and primitive Kazakhoceras that are the of central Texas contain a rich and abundant ammonoid earliest known records for the latter genus in the world. fauna, much of which has been previously documented While there are no taxa in common with those found in (Gabb 1862, Plummer & Scott 1937, Miller & Youngquist Asbian strata of the Antler Foreland Basin or northern 1948, Titus 1999). All published specimens from this re- Alaska, the overall character of the assemblage demon- gion are late Brigantian or Serpukhovian in age. However, strates it is Asbian (B1) and roughly equivalent to, or more collecting by ALT at the famous Chappel Hill quarry loca- probably, slightly older than the earliest Asbian lity near San Saba in the fall of 2007 confirmed that Gonia- ammonoids found in Utah and eastern Nevada. tites multiliratus Gordon, 1962 and Girtyoceras mesleria- num (Girty, 1909) occur in tan-coloured, punky concretions about 1 metre above the base of the Barnett, Marathon-Ouachita Foreland Basin which appears to be the oldest Mississippian ammonoid fauna in the region. From our analysis of both published and unpublished data, Asbian ammonoids have not yet been collected from the Arbuckle Mountains (Oklahoma). – Early Brigantian am- southern midcontinental United States. This region’s re- monoids are very common in the Caney Formation of the cord appears to begin in the upper portion of the early Bri- Arbuckle Mountains area, south Central Oklahoma (Gor- gantian and continues almost unbroken through the early don 1970). The first description of this fauna was made Serpukhovian (Saunders et al. 1977, Gordon 1965). Four over 100 years ago (Girty 1909). In that paper, the follow- principle areas, all within the general Marathon-Ouachita ing species were listed (with our revisions) from several Foreland Basin trend, have produced nearly all of the localities: ‘Goniatites choctawensis Shumard, 1863’ known Goniatites Zone specimens. From west to east, [= Goniatites multiliratus Gordon, 1962 (part)], ‘Goniati- these are; (1) the Sierra Diablo Mountains (west Texas), (2) tes newsomi Smith, 1903’ [= Pachylyroceras newsomi the Llano Plateau (central Texas), (3) the Arbuckle Moun- (Smith, 1903)], ‘Adelphoceras meslerianum Girty, 1909’ tains (south central Oklahoma), and (4) the eastern Ozark [= Girtyoceras meslerianum (Girty, 1909)], ‘Gastrioceras Plateau (Batesville area of north-eastern Arkansas), each to caneyaum Girty, 1909’ [= Neoglyphioceras caneyaum be discussed separately below. All the ammonoid bearing (Girty, 1909)], ‘Trizonoceras lepidum Girty, 1909’ (= Tri- concretionary black shale units are located on the northern zonoceras lepidum Girty, 1909). side of the foreland basin, bordering the continental shelf Following the designation of a neotype for Goniatites (Gordon 1965, 1970; Saunders et al. 1977). choctawensis Shumard, 1863 (now referred to Dom- barites) by Branson et al. (1959), Gordon (1962, 1965) Sierra Diablo Mountains. – No systematic analysis of Vi- postulated that the material described by Girty (1909) came séan ammonoids from the Sierra Diablo Mountains has from at least two different stratigraphic horizons; a lower ever been published. However, King (1965) listed eight Vi- one containing a more finely ornamented species for which séan species from the Barnett Formation; ‘Goniatites cre- he erected the name Goniatites multiliratus, and an upper nistria Phillips, 1836’, ‘Goniatites choctawensis Shumard, one bearing “Goniatites” choctawensis Shumard. He further

111 Bulletin of Geosciences • Vol. 86, 1, 2011 stated that G. multiliratus and the co-occurring Lower Moorefield Formation: ‘Goniatites aff. G. creni- Girtyoceras meslerianum (Girty, 1909) were only present stria Phillips, 1836’ (= Goniatites eganensis sp. nov.), at Girty’s stations 2081 and 2083. Because our own field- ‘Girtyoceras welleri Gordon, 1965’ (= Girtyoceras welleri work has demonstrated that a relatively complete late early Gordon, 1965). and late Brigantian ammonoid record exists in the Caney Upper Moorefield Formation: ‘Goniatites multiliratus Formation, we concur with Gordon and come to the con- Gordon, 1962’ (= Goniatites multiliratus Gordon, 1962). clusion that Goniatites multiliratus Gordon, 1962 and Girtyoceras meslerianum (Girty, 1909) are the only Goniatites Zone ammonoids actually figured by Girty. Present study and stratigraphic background Miller & Furnish (1940) erected Epicanites loeblichi based on material from the Caney Formation collected Antler Foreland Basin south of Ada, Pontotoc County, Oklahoma. According to Gordon (1965), these specimens were secured from the All of the Nevada and Utah material described in this study Goniatites multiliratus interval of the Deleware Creek was assembled from 94 field collections (Appendix B) Member and therefore are from the upper portion of the made at 18 general localities in east-central Nevada and Goniatites interval. Additional specimens of Girtyoceras west-central Utah (Figs 2, 3). Most specimens were collec- meslerianum (Girty, 1909) from the Wapanucka area of ted from the Concretionary Phosphatic Shale Member of Oklahoma were also described and illustrated by McCaleb the Chainman Formation of Poole & Sandberg (1991), et al. (1964). Drahovzal (1972) reviewed Goniatites Zone which was subsequently referred to the lower portion of the assemblages from Oklahoma, listing only Goniatites Camp Canyon Member (Sadlick 1995). In its type area, the multiliratus Gordon, 1962 and Girtyoceras meslerianum Camp Canyon Member rests conformably on the Skunk (Girty, 1909). Thus, three taxa have been described from Spring Member and is conformably overlain by the Willow the upper portion of the Goniatites Zone in the Deleware Gap Member (Fig. 4). Camp Canyon lithologies are prima- Creek Member of the Caney Formation: Epicanites rily dark grey or black coloured fissile or non-fissile shale loeblichi Miller & Youngquist, 1940, Goniatites and grey or tan weathering siltstone. Subordinate amounts multiliratus Gordon, 1962, and Girtyoceras meslerianum of sandstone, nodular and granular phosphate, and bedded (Girty, 1909). or concretionary micritic carbonate occur locally. In gene- ral, good exposures of the Camp Canyon Member are un- Eastern Ozark Plateau (Arkansas). – Starting with Smith common. (1903), which is among the earliest reports of an ammo- The Camp Canyon Member can be recognized consis- noid from the Goniatites Zone in North America, a number tently over eastern Nevada and west-central Utah, however of authors (e.g. Girty 1911; Gordon 1965, 1970) have re- the overall thickness, lithology, and age varies widely, de- ferred specimens collected from the lower portion of the pending on position relative to the ancient Antler Highland Moorefield Formation in the Batesville area (fide Gordon (Fig. 4). Despite this complexity, three primary facies belts 1965) to Goniatites crenistria Phillips, 1836. However, the can be recognized within the Viséan age portion of the wide lobes and deep ventral saddles in the sutures of these Camp Canyon Member. From west to east these are: (1) a specimens preclude them from that taxon. Smith (1903) proximal foredeep sequence of greater thickness (exceed- also described and illustrated specimens of Girtyoceras ing 500 metres) and a marked presence of siderite concre- collected from lower Moorefield Formation beds associa- tions and sandstone; (2) a medial foredeep sequence char- ted with “G. crenistria” that were erroneously referred to acterized by condensed sequences, an abundance of the nomen dubium “Glyphioceras calyx (Phillips, 1836)”. siltstone and nodular and granular phosphate, and general This material was redescribed and re-illustrated by Gordon lack of siderite and sandstone; (3) a distal foredeep/lower (1965) who referred the Goniatites specimens to G. aff. carbonate ramp facies characterized by sediments from crenistria Phillips, 1836 and erected a new species of Gir- eastern sources, abundant nodular and granular phosphate, tyoceras, G. welleri Gordon 1965, for the specimens refer- siltstone, and the presence of lower (distal) ramp facies red to Glyphioceras calyx. In that same work, Gordon fine-grained carbonate beds. The Viséan–early Ser- (1965) also illustrated and described crushed specimens of pukhovian interval in the Chainman Formation is essen- Goniatites multiliratus Gordon, 1962 from slightly higher tially conformable through most of the study area, but may stratigraphically than the horizon yielding the crenistriate exhibit highly condensed intervals with few or no body fos- forms. Drahovzal (1972) reviewed the Goniatites Zone as- sils due to sediment starved depositional systems, particu- semblages of Arkansas and reiterated the same conclusions larly in central and eastern White Pine County, Nevada. as Gordon (1965). In summary, the following forms, with We see no compelling biostratigraphic or stratigraphic evi- our revisions, have been reported from the Goniatites Zone dence in the study area for the widespread lower Chesterian of Arkansas by Gordon (1965). (early Brigantian) regional angular unconformity hypothe-

112 Dieter Korn & Alan L. Titus • Goniatites Zone (middle Mississippian) ammonoids, Nevada and Utah

Figure 4. Facies scheme for the Chainman Formation in the Antler Fore- land Basin. Abbreviations: DW – Duck- water Hills; CC – Cathedral Canyon; HC – Hamilton Canyon; TSC – Trough Springs Canyon; RS – Rosebud Spring; JW – Jensen Wash; SB – South Burbank Hills; NR – Needle Range; GM – Gran- ite Mountain; MC – Middle Confusion Range; LS – limestone; while ellipses – limestone concretions; black ellipses – siderite concretions.

sized by Trexler et al. (1995) at the base of their Newark mens of Goniatites eganensis sp. nov. and Goniatites so- Canyon Sequence. Available evidence possibly points to werbyi sp. nov. (10NVNY-1). an earlier forebulge migration driven unconformity that had already reached western Utah by middle Meramecian Hamilton Canyon. – The Chainman Formation is at least time (Sandberg et al. 2008). 750 metres thick in the White Pine Range of western White Pine County, Nevada. Surface outcrops are extensive (Humphrey 1960, Hose & Blake 1976), but good exposu- Proximal Foredeep res are rare, generally being limited to recently eroded arro- yos and canyons. Exposures yielding Viséan ammonoids Duckwater Hills. – Ammonoids were reported by Young- appear to be concentrated on the west side of the range be- quist (1949a) from the Duckwater Hills locality in Nye tween Cathedral Canyon and the north end of Hamilton County (Fig. 2) where the Camp Canyon Member is well Canyon (Fig. 2), however we did not exhaustively survey exposed in a broad, north-south trending strike valley the region and there is tremendous unexplored potential, bounded on the west by the Devonian Devils Gate and Jo- especially north of Highway 50. The Goniatites Zone inter- ana formations and to the east by Neogene volcanic units val is at least 200 metres thick but so far we recognize only (Kleinhampl & Ziony 1985). All of Youngquist’s reported three horizons, all of which are in the upper part. Late Bri- material from this locality is Pendleian (early Serpukho- gantian, early, middle, and late Pendleian, and middle Arns- vian) in age. In 1993, ALT discovered that the section is re- bergian ammonoids are also common in the area. The best latively continuous (Fig. 5), well-exposed, and produces exposures of Goniatites Zone strata are in a series of ammonoids well down into the late Viséan. Both early and west-northwest trending drainages north of the abandoned late Brigantian ammonoids are common. Three- town of Hamilton (Fig. 5) where four collections dimensionally preserved early Brigantian material was (95NVWP-15, 95NVWP-17, 07NVWP-3) were made found in two prominent septarian concretion horizons that from a horizon of grey and orange brown weathering con- occur about 48 metres below the Viséan-Serpukhovian cretions (bed 44). This horizon has a relatively diverse as- boundary or 78 metres below the top of the exposed sec- semblage dominated by Goniatites eganensis sp. nov. and tion, which ends in late Pendleian strata. The lower septa- Girtyoceras hamiltonense sp. nov., but also containing rian horizon (bed 4) is locally packed with specimens of Praedaraelites loeblichi (Miller & Furnish, 1940), and Me- Goniatites deceptus sp. nov. and rare Girtyoceras hamilto- tadimorphoceras richardsi sp. nov. Measured sections in- nense sp. nov. Although many specimens exhibit septarian dicate this horizon is at least 190 metres above the base of disruption, overall the material is excellently preserved. A the Chainman Formation. total of three collections were made from this horizon (93NVNY-1, 07NVNY-2, 07NVNY-4). The upper hori- Eberhardt Mill (Cathedral Canyon or Shermantown Ca- zon (bed 9), which is approximately 1.5 metres higher and nyon). – Large areas mapped as Chainman Formation oc- above a bright orange sandstone unit, contains rare speci- cur not far south of the Hamilton Canyon area, just east of

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Figure 5. Columnar sections with the lithostratigraphy, ammonoid biozones, bed numbers, and ammonoid samples of the Duckwater Hills and Hamilton Canyon sections. Abbreviations: G. ega- nensis – Goniatites eganensis Ammon- oid Biozone.

the mouth of Shermantown Canyon (Humphrey 1960). G. deceptus horizon from which were secured a few non- However, until recent erosion triggered by fire denudation diagnostic fragments of Girtyoceras. Goniatites eganensis in 2006–2007, the exposures were generally poor. The fires assemblage taxa were not found at this locality but presu- and erosion have temporarily created excellent exposures mably occur upsection as at the Duckwater Hills (see of Chainman Formation just south of the classic Eberhardt above). Mill site in the White Pine Mountains (Fig. 2). In 2007 DK and ALT secured numerous specimens of beautifully pre- served Goniatites deceptus sp. nov. and rare Girtyoceras Medial Foredeep hamiltonense sp. nov. (07NVWP-5) from concretionary lenses packed with leiorhynchid brachiopods and cephalo- Trough Springs Canyon. – The south-eastern side of the pods that occur approximately 80 m above the base of southern Egan Range has a broad north-northeast trending the exposed section. A second, lower horizon of dark grey strike valley formed in east dipping beds of the Chainman concretions occurs approximately 20 metres below the Formation and Scotty Wash formations (Tschanz &

114 Dieter Korn & Alan L. Titus • Goniatites Zone (middle Mississippian) ammonoids, Nevada and Utah

Figure 6. Columnar sections with the lithostratigraphy, ammonoid biozones, bed numbers, and ammonoid samples of the Trough Springs Canyon, Rosebud Spring, and Pony Express Canyon sec- tions. Abbreviations: N – Needle Mem- ber; Sk – Skunk Spring Member; G. eganensis – Goniatites eganensis Ammonoid Biozone; C. arcticum – Calygirtyoceras arcticum Ammonoid Biozone.

Pampeyan 1970). Unfortunately, the Camp Canyon Mem- tion (93NVLI-3). The presence of benthic elements at this ber is well exposed in only one area, just north of where the horizon, which correlates with a similar occurrence of ben- Trough Springs Canyon road forks north and south into the thic fauna at the Pony Express Canyon locality, indicates strike valley (Fig. 2). This section is interpreted, along that conditions even in this portion of the basin did briefly with those at Rosebud Spring and Pony Express Canyon, as become only mildly disaerobic in the early Brigantian. having been deposited in some of the deepest-water, Most Brigantian concretions at Trough Springs have a grey most-offshore settings in the study area (Fig. 6). Although to tan punky appearance, and are partly “de-calcified” with early Serpukhovian ammonoids are abundant, Viséan am- most specimens occurring as yellow-orange coloured li- monoids are not common, probably as a function of corro- monitic steinkerns and replacements that crumble easily sion, corrasion, bioerosion, and early diagenetic removal during collection. Although this diagenetic alteration des- of aragonite shells rather than an ecological or physical troyed the quality of many specimens, some individuals are barrier to the presence of living animals in the water co- excellently preserved. A single uncrushed specimen of Go- lumn. Low oxygen levels near the sediment-water inter- niatites eganensis was also collected from bed 5 about four face are also indicated by a general lack of shelly benthos metres below 93NVLI-3 in a 25 millimetre diameter phos- in concretions and on shale bedding surfaces. A single phate concretion (93NVLI-2). Crushed lirate Goniatites cf. non-septarian concretionary horizon (bed 6) packed with G. deceptus sp. nov., also occur in a poorly exposed tan- the remains of ammonoids (Goniatites eganensis sp. nov. grey septarian concretionary horizon (bed 2) around nine and Goniatites sowerbyi sp. nov.), gastropods, bivalves, metres below 93NVLI-3. The material from bed 2 is poorly and leiorhynchid brachiopods did produce a large collec- preserved and no collection was made.

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Rosebud Spring. – Carboniferous ammonoids have long Distal Foredeep/Shelf Margin been known from this general area (Fig. 2), which was re- ferred to as the Connor’s Pass locality by Youngquist Battleship Wash. – Lirate Goniatites occur abundantly in a (1949a). Because Connor’s Pass (or Connor’s Summit) is packstone carbonate within the middle portion of the Bat- actually located several kilometres to the east of the loca- tleship Wash Formation at and around the type section in lity, we have renamed it after the nearest physiographic fea- Battleship Wash, Clark County, Nevada. They are just be- ture, Rosebud Spring. The structural geology of this part of low a major sequence boundary marked by a disconformity the Schell Creek Range is complex (Hose & Blake 1976) and terra rossa, which may explain their apparent absence and intact, exposed sections of the Camp Canyon Member just to the north at the Mid-Carboniferous Global Strato- are rare. However, at Rosebud Spring, a moderately type Section and Point in Arrow Canyon. The specimens north-dipping section appears to be relatively intact from at are poorly preserved, coarsely re-crystallized calcite shells least the Asbian through the early Serpukhovian. As at that bond very tightly to both external moulds and stein- Duckwater, all previously published material from Rose- kerns. A protracted collecting effort (04NVCL-1) by ALT bud Spring is early Serpukhovian (Pendleian) in age. In in the company of Barry Richards, who brought the occur- 1993, ALT found the Rosebud Spring Camp Canyon rence to the attention of the former, yielded only a single Member section also yields Asbian and late Brigantian am- diagnosable fragment showing traces of pronounced lirate monoids. The lowest known Viséan ammonoid bearing ho- ornament. The strength and density of the lirae suggests the rizon is a row of mostly non-septarian, medium-grey weat- Battleship Wash taxon is either Goniatites deceptus sp. hering 0.75 m diameter concretions (bed 1) exposed on the nov. or Goniatites multiliratus Gordon, 1962. Pendleian east side of the Rosebud Spring drainage (Fig. 6). A few ammonoids also occur in the upper portion of the Battles- specimens of Goniatites americanus Gordon, Calygirtyo- hip Wash Formation at its type section, demonstrating it is ceras arcticum Gordon, Entogonites sp., and Kazakhoce- comprised almost entirely of early Brigantian and early ras bylundi sp. nov. were secured in four separate collecti- Pendleian highstand sequences. Because the specimens are ons (93NVWP-1, 95NVWP-3, 98NVWP-1, 07NVWP-2). so poorly preserved, the locality is mentioned only because A prominent horizon of orange-tinted large septarian con- of the area’s general significance to Carboniferous stratig- cretions (bed 9) that we correlate with similar concretions raphy. in the upper portion of the early Brigantian at localities both to the east and west, occurs about 8 metres upsection. Granite Mountain. – The Granite Mountain locality lies at No diagnostic material was collected from this horizon, but the north end of the long belt of Chainman outcrops stret- distinctive late Brigantian ammonoids such as Pachylyro- ching across west-central Utah (Fig. 3). The Chainman ceras and Lusitanoceras occur within fifteen metres upsec- Formation crops out extensively along the lower east slo- tion (sample 93NVWP-3) suggesting the septarian interval pes of Granite Mountain proper (Hose 1974), which con- is late early Brigantian in age and that the section is highly trary to its name, is composed mostly of Carboniferous age condensed because of sediment starvation. limestone. The localities’ Viséan stratigraphy is described in detail by Webster et al. (1984), although our observati- Pony Express Canyon. – Good outcrops of Chainman For- ons suggest revisions are needed, as was also suggested in mation are uncommon in the Antelope Range, located Silberling et al. (1995). north-east of Ely. However, relatively good exposures of A prominent phosphate pebble lag conglomerate bed the Needle and Camp Canyon members and the underlying containing abraded solitary rugose corals and pelmetozoan Joana Limestone do occur in the vicinity of Pony Express debris (bed 8) was identified by Webster et al. (1984) as the Canyon (Hose & Blake 1976), on the east side of the range base of the Carboniferous at Granite Mountain (Fig. 7). We (Fig. 2). Numerous crenistriate Goniatites eganensis sp. have secured several specimens of Goniatites sp. nov. and rare Girtyoceras hamiltonense sp. nov. (04UTJU-2) from this unit suggesting it is no older than (99NVWP-1) associated with the brachiopod Leiorhyn- Asbian in age. The phosphatic unit overlies a series of chus sp. were collected by ALT from a single horizon of black shale beds with bluish grey weathering micrite con- highly fossiliferous concretions (bed 10) that occur about cretions that are very similar to overlying beds. There is no 3.7 metres above what is believed to be the Skunk Spring abrupt lithologic change where the section appears to be Member (Fig. 6). Three metres above this lower ammonoid relatively complete. An abrupt lithologic change occurs bearing horizon are small maroon-to-brown-weathering si- several metres down section from the pebble lag unit where derite concretions bearing uncommon late Brigantian am- black shales and micrites are underlain by tan weathering monoids such as Pachylyroceras (99NVWP-2), indicating siltstones and brown weathering fine sandstones. We did the section, in similar fashion to that at Rosebud Spring, not conduct any biostratigraphic analysis of the sub-con- has a highly condensed Asbian–early Brigantian interval, glomerate beds, and so cannot confirm their correlation probably due to distance from sediment sources. by Sandberg et al. (2008) with the Viséan-age Delle

116 Dieter Korn & Alan L. Titus • Goniatites Zone (middle Mississippian) ammonoids, Nevada and Utah

Figure 7. Columnar sections with the lithostratigraphy, ammonoid biozones, bed numbers, and ammonoid samples of the Granite Mountain section. Abbrevi- ations: Sk – Skunk Spring Member; C. arcticum – Calygirtyoceras arcticum Ammonoid Biozone; Gt. primum – Girtyoceras primum Ammonoid Bio- zone; G. deceptus – Goniatites deceptus Ammonoid Biozone.

Phosphatic Member. No Joana Formation is exposed any- Contrary to Webster et al. (1984), we tentatively assign this where in the area and it is believed that the unit was either unit to the Skunk Spring Member. Almost 8 metres above stripped off or never deposited in an area named the ‘Gran- this unit is a prominent row of elliptical hard blue grey con- ite Mountain Island’ by Sandberg et al. (2008). Erosional cretions with ammonoids (bed 17). This is the type horizon truncation of the Joana Formation in the Bishop Springs and locality for G. americanus Gordon, 1971. Four collec- Dome area to the south certainly suggests that post-Joana, tions were made from this bed, both at the type locality pre-Chainman uplift occurred in the region. (94UTJU-1, 07UTJU-1) and along strike to the north At the southern end of the best Granite Mountain expo- (07UTJU-2, 07UTJU-3). These collections contain Gonia- sures, near the measured section reported by Webster et al. tites americanus Gordon, 1971, Calygirtyoceras confu- (1984), approximately eight metres above the phosphate sionense sp. nov., C. arcticum (Gordon, 1957), Ento- pebble lag unit there is a poorly fossiliferous micrite (bed gonites sp., Kazakhoceras bylundi sp. nov., Bollandoceras 10) that falls at the approximate correct stratigraphic and occidentale sp. nov., Dimorphoceras rileyi sp. nov., and biostratigraphic position for the Skunk Spring Member Praedaraelites loeblichi (Miller & Furnish, 1940). (lower portion of the Goniatites americanus interval). Another similar concretionary horizon occurs just below

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Figure 8. Columnar sections with the lithostratigraphy, ammonoid biozones, bed numbers, and ammonoid samples of the sections in the Confusion Range. Abbreviations: Sk – Skunk Spring Member; C. conf. – Calygirtyoceras confusionense Ammonoid Biozone; C. arcticum – Calygirtyoceras arcticum Ammonoid Biozone; Gt. primum – Gir- tyoceras primum Ammonoid Biozone.

the massive cherty carbonate unit assigned by Webster et Mountain “endothyrid bearing” unit with underlying and al. (1984) to the Skunk Spring Limestone Member. This overlying black shale units suggests that it is a locally- concretionary horizon (bed 22) was found to contain a sin- emplaced semi-consolidated “olistholith” derived from a gle nodule with several specimens of G. americanus shallower water setting, perhaps the “Granite Mountain Is- (97UTJU-2). We believe that the overlying relatively land” uplift (see Sandberg et al. 2008). Unfortunately, thick, “endothyrid-bearing” limestone unit correlated with there are also a number of obvious post-Palaeozoic low an- the Skunk Spring Limestone by Webster et al. (1984) does gle and high angle fault structures that complicate inter- not actually correlate with any carbonate unit at any of the preting the origin of this unusual bed. other Chainman sections we examined. Ammonoid Regardless of its origin, locally the “olistolith” yields biostratigraphic data also refutes Silberling et al.’s (1995) large numbers of well-preserved Goniatites americanus correlation of the Granite Mountain “endothyrid bearing” Gordon, 1971, Calygirtyoceras arcticum (Gordon, 1957), unit with a prominent upper Brigantian carbonate unit in Girtyoceras primum sp. nov., Entogonites acus sp. nov., the type Skunk Spring area (our Middle Confusion Range Dimorphoceras rileyi sp. nov., and Praedaraelites sections) because the former carries a Girtyoceras primum loeblichi (Miller & Furnish, 1940) (94UTJU-2, 94UTJU-3, assemblage in its uppermost beds, while the latter overlies 94UTJU-4, 94UTJU-9, 04UTJU-3, 05UTJU-12), both in shales bearing Dombarites and Edmooroceras. Given its its upper beds and in concretionary masses (bed 25) that position in the middle of the range of Goniatites develop irregularly around its upper margin or between americanus, the Granite Mountain “endothyrid bearing” pinch and swell lobes. Overlying this unit, approximately unit obviously correlates in its entirety with shale intervals 24 metres of black concretionary shale yields ammonoids at our other localities. The age, internally contorted fabric, at two separate concretionary horizons (beds 33, 35) pinch and swell geometry, and relationship of the Granite both of which contain Goniatites deceptus sp. nov.

118 Dieter Korn & Alan L. Titus • Goniatites Zone (middle Mississippian) ammonoids, Nevada and Utah

(94UTJU-3b, 94UTJU-5, 94UTJU-10, 97UTJU-4, 05UTJU-13, 05UTJU-14). A phosphate-pebble lag con- taining abundant crinoidal debris (bed 40) yields sparse Dombarites cf. D. choctawensis Shumard, Neoglyphio- ceras sp. and Girtyoceras sp. (94UTJU-11, 10UTJU-1), which is the basal most assemblage above the Goniatites zone.

Bishop Springs Dome. – Because of complicated structure and extensive cover, we only found one place where the Goniatites interval can be observed in the Bishop Springs Dome area. Just west of where the road along the west flank of the structure turns east into a gap in the Joana Li- mestone, a relatively complete lower Chainman Formation section is present (Hose & Ziony 1963). Exposed is a thick section of Needle Member overlain by the 1.5 metre thick Skunk Spring Member and about 17 metres of the lower portion of the Camp Canyon Member. Large numbers of G. deceptus sp. nov. occur (93UTMI-50, 03UTMI-11, 03UTMI-12, 10UTMI-5) in a prominent row of 1–2 metre long septarian concretions (bed 8), about 11 metres above the top of the Skunk Spring Member. These are the only Goniatites zone ammonoids we observed at this locality, although other concretion horizons occur above and below this bed. Upper Brigantian ammonoids occur in small phos- phatic nodules approximately three or four metres higher.

Middle Confusion Range. – This is the type section of the Figure 9. Columnar sections with the lithostratigraphy, ammonoid Camp Canyon Member. The Chainman Formation is inter- biozones, bed numbers, and ammonoid samples of the sections in the mittently exposed along the Camp Canyon-Skunk Spring Conger Mountains. Abbreviations: N – Needle Member; Sk – Skunk Spring Member; G. dec. – Goniatites deceptus Ammonoid Biozone. Canyon road on the east side of the northern Confusion Range (Hose & Repenning 1964). The sections are situated in the east limb (west dipping beds) of a gently ceras bylundi sp. nov., Bollandoceras occidentale sp. nov., north-plunging syncline and are usually structurally sim- and indeterminate dimorphoceratids. Horizon three is three ple. In the handful of places where it is well exposed, am- metres above the last and is characterized by large 1–2.5 monoids ranging in age from Asbian to middle Pendleian metre long septarian concretions (93UTMI-23, can be collected. The best exposures are found approxima- 05UTMI-5, 05UTMI-7) from which were collected tely halfway between Skunk Springs and Ledger Canyon Goniatites americanus Gordon, 1971 and Metadimorpho- fork at three separate localities near the road (Fig. 3). We ceras sp. The intervening bed 8 yielded only Goniatites sp. have informally named these localities, trending in the (05UTMI-4). Slightly over 24 metres above the Skunk north direction, Middle Confusion 1, Middle Confusion 2, Spring Limestone is a septarian concretion horizon (bed 19 and Middle Confusion 3. of MC-1) that yields Goniatites deceptus sp. nov. Well-preserved Asbian-late Brigantian ammonoids are (93UTMI-24). These are the highest Goniatites Zone common and lower Goniatites Zone material has been col- ammonoids we found at the locality. lected from five horizons (Fig. 8). The lowest horizon is a non-septarian concretionary interval about 11 metres Conger Mountain West. – The west side of Conger Moun- above the base of the Camp Canyon Member from which tain (Fig. 3) has few good exposures of the lower Camp the following taxa have been collected (e.g. 07UTMI-3): Canyon Member from which ammonoids can be obtained Goniatites americanus Gordon, 1971, Calygirtyoceras even though Hintze (1974) mapped extensive outcrops. confusionense sp. nov., and Dimorphoceras rileyi sp. nov. Four separate collections were made from two large 1.2 meters higher is a closely spaced non-septarian concre- non-septarian concretion horizons (beds 19 and 21) that oc- tion couplet (beds 10, 10b of section 1) horizon (e.g. cur estimated 14 metres above the Skunk Spring Member 05UTMI-3, 05UTMI-9, 07UTMI-4, 07UTMI-5) that east of the road (01UTMI-40, 01UTMI-41, 01UTMI-42, yields Goniatites americanus Gordon, 1971, Kazakho- 01UTMI-43) that contain Goniatites deceptus sp. nov. and

119 Bulletin of Geosciences • Vol. 86, 1, 2011 indeterminate dimorphoceratids (Fig. 9). The local section 01UTMI-4, 07UTMI-2, 07UTMI-8) Goniatites ameri- appears to be largely condensed through the lower Goniati- canus, Girtyoceras gordoni sp. nov., and Dimorphoceras tes interval. However, at least two concretionary horizons rileyi sp. nov. The intervening concretionary horizon (bed (beds 14 and 16) in the G. americanus interval are present 14) did not yield any ammonoids. Five metres above bed (collections 01UTMI-46, 01UTMI-47). 16 are two closely spaced concretionary horizons (beds 24, 25) of which the higher (bed 25) contains Goniatites Conger Mountain East. – Exposures of the lower Camp Ca- eganensis sp. nov., Girtyoceras hamiltonense sp. nov., nyon Member containing concretions can be found almost Metadimorphoceras richardsi sp. nov., and Praedaraelites due east of Conger Spring (Fig. 3), west of the Skunk loeblichi (Miller & Furnish, 1940) (00UTMI-21, Spring-Camp Canyon road (Hintze 1974). Three small col- 01UTMI-5, 07UTMI-1, 07UTMI-9). Three septarian lections of ammonoids were made here: a lower one (bed concretionary horizons between beds 16 and 24 did not 14) containing Goniatites americanus Gordon, 1971, Ento- yield ammonoids. A horizon of small barren septarian con- gonites sp., and indeterminate dimorphoceratids cretions (bed 27) occurs approximately two metres above (01UTMI-48, 10UTMI-1) from approximately 12 metres bed 25, over which is a 1.5 m thick phosphate pebble lag above the Skunk Spring Member (Fig. 9), a middle one (bed that we consider late Brigantian in age. 18) consisting entirely of Goniatites deceptus sp. nov. (01UTMI-49) from six metres above the G. americanus ho- Jensen Wash. – The Chainman Formation is well exposed rizon, and an upper one (bed 20) another 1.5 m higher with for nearly its entire thickness at the Jensen Wash locality G. eganensis and Girtyoceras hamiltonense (10UTMI-2). (Fig. 3) of Webster et al. (1984), located on the north side of the Burbank Hills (Hintze 1997). Well-preserved am- South Burbank Hills. – Approximately 9 km north of the monoids occur through the entire Asbian-early Arnsber- intersection of the Big Jensen Pass road with paved high- gian stratigraphic interval, making the section particularly way 21, the Big Jensen Pass road jogs west around the significant from a biostratigraphic perspective (Fig. 10). south end of a ridge underlain by limestones of the Willow The lowest collections are from a concretionary hori- Gap Member (Hintze 1997). North-east of where the road zon (bed 7) that occurs 10 metres above the top of the jogs around the ridge, a couple of excellent exposures of Skunk Spring Member. Collections from that horizon the Camp Canyon Member occur in the middle of the (93UTMI-25, 97UTMI-9) contain Goniatites americanus north-east trending strike valley between the Joana Lime- Gordon, 1971, Calygirtyoceras arcticum (Gordon, 1957), stone and the Willow Gap Member (Fig. 3). The Skunk Calygirtyoceras confusionense sp. nov., Entogonites bore- Spring Member is not exposed, but the section starts with a alis Gordon, 1957, Dimorphoceras rileyi sp. nov., and tan weathering siltstone filled with abundant Lingula sp. Metadimorphoceras mangeri sp. nov. associated with the that is probably not more than a few metres above it. The brachiopod Leiorhynchoidea polypleura (Girty). About section (Fig. 10) is strikingly similar to those at the Middle one metre higher is a dark grey micrite concretion horizon Confusion Range locality. (bed 9, sample 97UTMI-10) containing Goniatites The lowest occurrence of ammonoids is in a americanus Gordon, 1971, and Entogonites borealis concretionary horizon (bed 2) about 0.5 metres above the Gordon, 1957. Lingula-bearing siltstone. Collecting from this horizon A thin, flaggy-weathering siltstone interval (bed 11) produced (00UTMI-22, 01UTMI-1) a few specimens of with abundant crushed Goniatites sp., Entogonites sp., and Goniatites americanus Gordon, 1971. Bed 4, about one indeterminate dimorphoceratids (97UTMI-11) occurs 25 metre above bed 2, yielded a more diverse assemblage centimetres above this. Within a distance of slightly less (01UTMI-2) containing Goniatites americanus Gordon, than two metres above the top of the siltstone are three 1971, Entogonites burbankensis sp. nov., Dimorphoceras closely spaced concretionary horizons, the lower and upper worki sp. nov., and Metadimorphoceras mangeri sp. nov. of which contain ammonoids. The lower horizon (bed 13) Bed 6 approximately one metre above bed 4, is a contains Goniatites americanus Gordon, 1971 and concretionary horizon that yielded numerous specimens Entogonites acus sp. nov. (97UTMI-12), while the upper (00UTMI-19, 01UTMI-3) of Girtyoceras primum sp. nov., horizon (bed 17) yielded Goniatites americanus Gordon, along with Goniatites americanus Gordon, 1971, Caly- 1971, and Girtyoceras primum (93UTMI-26). Bed 19 girtyoceras arcticum (Gordon, 1957), and Metadimorpho- (sample 97UTMI-13), about 1.5 metres above bed 17, ceras mangeri sp. nov. Bed 8 yielded the same assemblage yields Goniatites sp., Girtyoceras gordoni sp. nov., without the dimorphoceratids (07UTMI-6). The next Dimorphoceras rileyi sp. nov., and Kazakhoceras bylundi ammonoid bearing bed in the sequence is bed 12 which sp. nov. Six metres higher in the section are two closely yielded a few specimens (07UTMI-7) of Goniatites spaced horizons (beds 26 and 28) of large, frequently americanus Gordon, 1971. Approximately 3.5 m above septarian, grey weathering concretions that locally contain bed 12, bed 16 concretions yielded (00UTMI-20, abundant ammonoids. The assemblage in both of these

120 Dieter Korn & Alan L. Titus • Goniatites Zone (middle Mississippian) ammonoids, Nevada and Utah

Figure 10. Columnar sections with the lithostratigraphy, ammonoid biozones, bed numbers, and ammonoid samples of the Needle Range, South Burbank Hills, and Jensen Wash sections. Abbrevia- tions: Sk – Skunk Spring Member; C. conf. – Calygirtyoceras confusionense Ammonoid Biozone; C. arcticum – Calygirtyoceras arcticum Ammonoid Biozone; Gt. primum – Girtyoceras pri- mum Ammonoid Biozone; Gt. gordoni – Girtyoceras gordoni Ammonoid Bio- zone; G. deceptus – Goniatites deceptus Ammonoid Biozone.

horizons appears to be essentially same. Collections from and to the north of, Mountain Home Spring (Hintze 1986, the lower concretionary bed (26) include Goniatites sp. Hintze & Best 1987). Outcrops of the Camp Canyon Mem- indet. and Girtyoceras sp. indet. (97UTMI-14), while the ber are generally poor, but ammonoids were collected in upper bed (28) yields Goniatites deceptus sp. nov., three different areas. The first is located about 400 m north Girtyoceras hamiltonense sp. nov., Praedaraelites loeblichi and slightly east of where the Mountain Home Pass road (Miller & Furnish), and indeterminate dimorphoceratids enters the strike valley formed in the Chainman Formation (90UTMI-11, 93UTMI-27, 97UTMI-15, 04UTMI-1). The (Fig. 3). From here, a single non-septarian concretionary next ammonoids found in the section occur in bed 33, about horizon (bed 9) 0.75 m above a prominent tan weathering 5 metres above bed 28. This horizon, which is a phosphate siltstone packed with Leiorhynchoidea polypleura (Girty) pebble lag, yields rare Pachylyroceras sp. and is almost cer- was sampled. Collections from these concretions tainly late Brigantian in age (93UTMI-28). (00UTMI-13) contain Goniatites americanus Gordon, 1971 and Calygirtyoceras confusionense sp. nov., which Needle Range. – The Goniatites zone is discontinuously by its position directly over the Leiorhynchoidea polyple- exposed along the southwest-northeast trending road near, ura bed, must be very low in the Camp Canyon Member.

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The second area to be sampled is located approximately from lowest to highest, the ‘Goniatites americanus’, 1.5 km south and slightly west of where 00UTMI-13 was ‘Goniatites multiliratus’, and ‘Goniatites granosus’am- collected. Here, the Mountain Home Pass road passes monoid biozones. Gordon’s zones span the late Asbian and through good exposures of Camp Canyon Member, pass- Brigantian stages, and the lower two approximate the inter- ing just west of the Skunk Spring Member, which is also val of interest in this study. Gordon’s scheme has been used well exposed. This is where Sadlick (1965) measured his relatively unchanged until this work (e.g. Sadlick 1995). “Needle Range” section (Fig. 10). The lowest ammonoid Based on the presence of G. americanus in both Utah and bearing concretions occur 4 metres above the Skunk Spring Alaska, as well as the supposed presence of the Oklahoma Member (bed 7), just above the prominent Leiorhyn- species G. multiliratus in Utah and Nevada, this zonal sys- choidea polypleura bed seen to the north. Two small col- tem has been extended throughout the North American lections (00UTMI-14, 00UTMI-2n) from this horizon, continent (Gordon 1970). which is the same that produced 00UTMI-13, yielded Goniatites americanus Gordon, 1971 and Calygirtyoceras Present study. – Our new systematic appraisal of Asbian confusionense sp. nov. Five metres higher is a concre- and Brigantian ammonoids from the Great Basin and Uni- tionary horizon (bed 16) packed with ammonoids from ted States Midcontinent demonstrates two fundamental is- which Goniatites americanus Gordon, 1971, Girtyoceras sues that necessitate development of a new zonal scheme. primum sp. nov., and indeterminate dimorphoceratids were The Chainman Formation taxon thought by Gordon to re- collected (00UTMI-1n, 00UTMI-15). Approximately two present the Oklahoma species Goniatites multiliratus is in metres higher another concretionary bed (18) produced a fact an older homeomorphic form with a distinct suture and few Goniatites americanus Gordon, 1971 and indetermi- co-occurring assemblage. It is newly described here as Go- nate dimorphoceratids (00UTMI-6n). Almost six metres niatites deceptus sp. nov. Thus, we cannot confidently re- higher, a horizon of large septarians produced a few speci- cognize the species Goniatites multiliratus in the Chain- mens of Goniatites deceptus sp. nov. and Girtyoceras man Formation. It is probably present (e.g. bed 40 of hamiltonense sp. nov. (00UTMI-3n). A thin platy weather- Granite Mountain North section) along with Girtyoceras ing limestone with sparse crinoidal debris similar to bed 40 meslerianum (Girty, 1909), but the material is poorly pre- of the Granite Mountain section separates the lirate served and we cannot assign it to species without sutural goniatite concretionary bed from a five metre thick ?late data. Secondly, we have now documented a much higher Brigantian phosphate pebble lag interval (bed 23) which overall diversity than recognized by any previous study. yields ?Lusitanoceras sp. and Neoglyphioceras sp. With this better taxonomic discrimination, it is possible to (00UTMI-4n). demonstrate the study area preserves an exceptional record The third area from which ammonoids were collected is of the early evolution of Goniatites, Girtyoceras and Caly- 3 km south-west of Sadlick’s measured section, where the girtyoceras. The ubiquitous nature and relatively short Mountain Home Pass road turns sharply west. Immediately stratigraphic ranges of species of these genera help us to re- east of the road a few concretions were found weathering cognize seven biozones in roughly the same interval occu- from poor exposures of the Camp Canyon Member. pied by Gordon’s two (Figs 11, 12). The four lower biozones Goniatites americanus and Entogonites acus sp. nov. were are characterized by girtyoceratids and the three higher bio- collected from a single loose concretion (sample zones by species of Goniatites. These are detailed below. 07UTMI-10). There are several low angle faults cutting the immediate area and it was not possible to precisely esti- Calygirtyoceras confusionense Ammonoid Biozone. – The mate the stratigraphic position of this sample but it must be Calygirtyoceras confusionense range zone is defined as the from somewhere near bed 16. interval between the first occurrence of the zonal namebea- rer and first occurrence of Calygirtyoceras arcticum. Asso- ciated taxa include Entogonites borealis Gordon 1957 and Biostratigraphy Dimorphoceras rileyi sp. nov. (Fig. 12). It is best represen- ted by the lowest concretionary horizons at Jensen Wash Ammonoids and the Needle Range, but can also be recognized at the Middle Confusion Range section. Concretions from this Previous work. – Prior to Mackenzie Gordon’s pioneering zone typically have associated shelly benthos such as leior- work, all Late Viséan and early Serpukhovian ammonoids hynchid brachiopods as they occur just above the from the study area were placed into a single homogeneous brachiopod-rich basal beds of the Camp Canyon Member. faunal zone of little practical value (Miller & Furnish 1940, The zone cannot currently be recognized anywhere outside Youngquist 1949a, Miller et al. 1952). Gordon (1970; see Utah, but it is possible that it could be diagnosed in also Sadlick 1965, Webster et al. 1984) was able to recog- the Kuna Formation of Alaska as well as over most of the nize three distinct Late Viséan range zones, which are, Antler Basin.

122 Dieter Korn & Alan L. Titus • Goniatites Zone (middle Mississippian) ammonoids, Nevada and Utah

Figure 11. Stratigraphic correlation of chronostratigraphy, lithostratigraphic units, ammonoid zonations of various regions, and conodont succession of the Viséan.

It is important that the stratigraphic position of this Calygirtyoceras arcticum and the first appearance of Gir- zone is directly above the first appearance of the platform tyoceras primum sp. nov. The zonal index is typically a conodont Gnathodus bilineatus, which correlates roughly common and conspicuous component in assemblages within with the Meramecian-Chesterian series boundary in North the zone, however it is surprisingly uncommon in the Mid- America. This would suggest it is close in age to the fa- dle Confusion Range sections. Accompanying taxa include mous Greencastle ammonoid assemblage from the Ste. Goniatites americanus Gordon, 1971, Bollandoceras occi- Genevieve Limestone of west-central Indiana (Miller & dentale sp. nov. Dimorphoceras rileyi sp. nov., Kazakho- Gurley 1896, Smith 1903). The Greencastle assemblage is ceras bylundi sp. nov., and Entogonites borealis (Gordon, not currently known to contain Calygirtyoceras or 1957). It is especially well displayed at the Jensen Wash Entogonites, but it does contain primitive Goniatites (cf. (bed 7 to bed 9), Southern Burbank (below bed 6), and Gra- G. americanus Gordon, 1971), and primitive Kazakho- nite Mountain (bed 17 to 22) sections, but it is probably ceras (D.M. Work unpublished data, ALT, unpublished diagnosable in almost all the Utah Chainman Formation data) that are similar to those found in the lower G. ameri- outcrops. We designate Granite Mountain as the reference canus assemblages of Utah and Nevada. Thus it appears section for the zone. In addition, we also collected the zo- that the Greencastle assemblage is either an age equivalent nal namebearer at the Rosebud Spring section in eastern of, or more likely, slightly older than the C. confusionense Nevada, but poor ammonoid preservation in the sediment interval. starved eastern White Pine County sections prevents re- cognition of it over most of that area. It is possibly repre- Calygirtyoceras arcticum Ammonoid Biozone. – This zone sented in the lower portion of the Chainman Formation in is defined as the interval between the first appearance of western White Pine County and eastern Nye County where

123 Bulletin of Geosciences • Vol. 86, 1, 2011

Figure 12. Stratigraphic occurrence of the Asbian and early Brigantian ammonoid species in the Antler Fore- land Basin.

there is at least two hundred metres of section below lower Girtyoceras gordoni Ammonoid Biozone. – This zone is Brigantian ammonoid horizons. However, we have not se- defined as the interval between the first appearance of the cured any ammonoids of this general time frame from that zonal namebearer and the first appearance of Goniatites region probably due to facies controls. deceptus. Because the zonal namebearer is only found at The zone can be widely recognized in Alaska’s Kuna For- the Jensen Wash and South Burbank Hills sections, those mation, which is the type region for the zonal namebearer. are the primary reference sections, with the Jensen Wash Ammonoids of this age have not been recognized anywhere section being the type. Associated taxa include Goniatites else in North America primarily due to facies controls. americanus, Dimorphoceras rileyi sp. nov., and Kazakho- ceras bylundi sp. nov. Girtyoceras primum Ammonoid Biozone. – This zone is de- This zone cannot be recognized outside the type area in fined as the interval between the first appearance of Girtyo- western Utah, and is obviously an interval that is poorly rep- ceras primum sp. nov. and the first appearance of Girtyoce- resented in North America, primarily due to facies controls. ras gordoni sp. nov. It is readily diagnosed at most Utah We would expect it to be represented in the lower portion of Chainman Formation outcrops and its assemblage is the the Chainman Formation in the western portion of the study most consistently present of any in the lower zones. Jensen area, but as we have stated before, diagnostic ammonoids Wash (bed 13 to bed 18) is designated as the reference sec- have not yet been found there in the thick section below the tion for this zone because its relationship with the overly- Goniatites deceptus zone. As with all the earlier biozones in ing G. gordoni zone is best shown there. The Southern Bur- the eastern portion of the study area, this interval is a fos- bank Hills also shows this relationship and serves as a sil-poor nodular phosphate sequence that resulted from ex- supplemental reference section. treme sediment starvation. Although we cannot recognize Ammonoids from this zone are most abundant at Gran- this zone anywhere else in North America, it very likely ite Mountain where they can readily be shown to succeed could be represented in the Kuna Formation of the Lisburne those of the Calygirtyoceras arcticum Ammonoid Group and correlative strata in northern Alaska. Biozone. Here the G. primum assemblage is largely associ- ated with the thick carbonate allochthonous body (bed 24) Goniatites deceptus Ammonoid Biozone. – This zone is de- mistakenly referred to the Skunk Spring Limestone by fined as the interval between the first appearance of the zo- Gordon (1971) and others (e.g. Webster et al. 1984). Am- nal namebearer and the first appearance of Goniatites ega- monoid taxa associated with G. primum include Goniatites nensis sp. nov. This is the first zone that can be widely americanus Gordon, 1971, Calygirtyoceras arcticum recognized across the entire study area. Virtually every (Gordon, 1957), Entogonites acus sp. nov., Dimorpho- section we examined outside of the central starved sedi- ceras rileyi sp. nov., Metadimorphoceras mangeri sp. nov., ment facies belt that has this interval exposed yields well and Praedaraelites loeblichi (Miller & Furnish, 1940). preserved ammonoids. Large collections from this zone This zone cannot be recognized with certainty outside of were made at the Duckwater, Jensen Wash, Granite Moun- the Great Basin region of the USA, but it is probable that it tain and Middle Confusion sections. The Southern Bur- would eventually be recognized in the Kuna Formation of bank Hills section is selected as the primary reference sec- the Lisburne Group in Alaska. tion for the zone because there it is possible to recognise

124 Dieter Korn & Alan L. Titus • Goniatites Zone (middle Mississippian) ammonoids, Nevada and Utah both its lower and upper limits. Assemblages in this zone tion probably represent G. multiliratus and G. mesleria- are thoroughly dominated by the genus Goniatites (G. de- num, but additional collecting is needed to confirm this. In ceptus sp. nov.), but also yield Praedaraelites loeblichi the eastern part of the study area this interval is typically a and small, indeterminate dimorphoceratids. We cannot sediment-starved phosphate pebble or grain-bearing black currently recognize this zone anywhere outside the study shale yielding only very rare macrofossils. In western sec- area. tions, the interval is mostly a thick septarian concretion-bearing shale interval that yields only rare fos- Goniatites eganensis Ammonoid Biozone. – This zone is sils and virtually no ammonoids. The zone can be readily defined as the interval between the first appearance of Go- recognized at all of the Texas, Oklahoma, and Arkansas niatites eganensis sp. nov. and the first appearance of Go- sections discussed above. Recent collecting by ALT has niatites multiliratus Gordon 1962. It can be recognized on also shown it to be the lowest recognizable ammonoid zone both the east and west margins of the study area, but un- in the Barnett Shale of the Llano Uplift region near San like the previous Goniatites deceptus zone, it can also be Saba, Texas, where the zonal index and Girtyoceras recognized, because of lowered sea levels, in the central meslerianum commonly occur in calcareous concretions portion of the sediment starved belt (e.g. Trough Springs approximately one metre above the base of the formation. section). Because of the general lack of G. multiliratus in The girtyoceratids Sulcogirtyoceras and Edmooroceras the Great Basin region due to widespread sediment star- succeed Girtyoceras meslerianum in both the Great Basin vation at its top, no single section contains a complete re- and Midcontinent US sections, but evaluation of these as- cord of the zone. However, the Southern Burbank Hills semblages is beyond the scope of this paper. and White Pine Range sections are excellent references for its lower boundary. Assemblages from this interval contain, in addition to the zonal nominate species, Girtyo- Conodonts ceras hamiltonense sp. nov., Metadimorphoceras richard- si sp. nov., and Praedaraelites loeblichi (Miller & Fur- Using conodonts, Sandberg et al. (1980) divided the inter- nish, 1940). val under study here into two zones; a lower Cavus- The Goniatites eganensis Ammonoid Biozone is the gnathus-Paragnathodus homopunctatus Conodont Bio- lowest of the Brigantian zones in this study that we can rec- zone and an upper Cavusgnathus-Gnathodus girtyi girtyi ognize elsewhere in North America. The zonal index Conodont Biozone. We have concluded that these two zo- ammonoid occurs widely on the northern margin of the nes roughly correspond respectively to Gordon’s Goniati- Ouachita-Marathon Foreland Basin sequence, where it has tes americanus and Goniatites multiliratus Ammonoid been consistently and mistakenly referred to Goniatites Biozones. However, no attempt was made by either of crenistria (e.g. Smith 1903, Girty 1911, Gordon 1965). those authors to make a firm correlation with the other’s Based on our own collecting and evaluation of the literature, zonal scheme and higher precision correlation between the we now recognize this zone at the following localities: two systems is not presently possible. We suspect, as in Helms Formation (Barnett of some authors) in the northern previous ammonoid studies, that the conodont diversity Sierra Diablo Range, Texas; Caney Shale, on both the north and stratigraphic resolution is underrepresented in previ- and south sides of the Arbuckle Mountains, Oklahoma; up- ous work and that this would be a fruitful area for future re- per portion of the Moorefield Formation (sensu Gordon search. Tynan (1980) did report the first occurrence of the 1965), Batesville, Arkansas. In all of the eastern sections the platform element Gnathodus bilineatus, an extremely im- ammonoids of this zone are the lowest found in the portant global biostratigraphic datum within the early As- Brigantian succession and are overlain by Goniatites bian, to be in the top of the Skunk Spring Limestone Bed multiliratus-Girtyoceras meslerianum assemblages. (Fig. 11) in his Needle Range section and referred the pre- sent study interval to his ‘Lower Zone A’. This demonstra- Goniatites multiliratus Ammonoid Biozone. – Defined as tes that the top of the Skunk Spring Member contains the the interval between the first appearance of the zonal index Meramecian-Chesterian series boundary (Repetski & ammonoid and Sulcogirtyoceras limatum (Miller & Faber, Stamm 2009) and that the lowest beds of the Camp Canyon 1892), this zone can only tentatively be recognized in the Member are equivalent to the Ste. Genevieve Limestone of Great Basin region at the Granite Mountain section where the Mississippi River Valley (type area for the Chesterian). it is the highest zone in the stratigraphic interval targeted by this study. The primary reference sections are designa- ted as the Caney Shale outcrops near Ada, Pontotoc Calcareous foraminifera County, Oklahoma, which yielded the types for the nomi- nate species (Gordon 1965). Poorly preserved ammonoids Webster et al. (1984) divided the study interval into two collected from bed 40 of the Granite Mountain North sec- zones based on calcareous foraminifera; a lower interval

125 Bulletin of Geosciences • Vol. 86, 1, 2011 assigned to Mamet Foraminiferal Zone 15 and an upper in- girtyoceratids, for instance show a very clear, gradual evo- terval referred to Mamet Foraminiferal Zone 16i. As a rule, lution in the Antler Foreland Basin, which is difficult to calcareous foraminifera do not occur in the deep-water compare with the more iterative pattern in the North black shale sequences from which most of the ammonoids Variscides. in this and other studies were collected. Fortunately, they In spite of these problems, we propose the following do occur in abundance in the allochthonous carbonate body two key ammonoid events are particularly useful for inter- (our bed 24 of the Granite Mountain section) erroneously continental correlation; (1) the lowest occurrence of char- referred to the Skunk Spring Limestone Bed by Webster acteristic Girtyoceras (e.g. G. primum sp. nov.), and (2) the et al. (1984). Foraminifera diagnostic of MFZ-15 (Eoendo- lowest occurrence of Sulcogirtyoceras. Other indicators thyranopsis utahensis Zeller assemblage) occur through all such as the ranges of Entogonites and Calygirtyoceras can but the highest one metre of this unit, while the upper metre also be used for correlation in a more general way. In addi- contains a Neoarchaediscus-early Zellerinella assemblage tion, key global foraminiferal and conodont events (first diagnostic of MFZ-16i. Thus, the boundary between these occurrences of Neoarchaediscus and Gnathodus bili- two zones, which approximates the foraminifera-based neatus, respectively) support our ammonoid-based datums Meramecian-Chesterian North American Stage Boundary and collectively serve as the basis for the global correla- advocated by Maples & Waters (1987), appears to occur tions discussed below. within the unit. As a result, we roughly correlate the 15–16i foraminiferal zone boundary with the Calygirtyoceras Great Britain (Craven Basin, Peak District). – Equivalent arcticum-Girtyoceras primum ammonoid zonal boundary successions in North England contain rich, well-preserved (Fig. 11). However, we want to note that this is at least two ammonoid faunas in thick basinal shale sequences that ammonoid zones higher than the currently accepted, have been well documented over the years by Bisat (1924, conodont-based Meramecian-Chesterian stage boundary 1934, 1952) and Moore (1936, 1946). They were summari- horizon (Repetski & Stamm 2009). Foraminifera diagnos- zed by Riley (1993) and updated by Korn & Tilsley (2006). tic of Mamet Foraminiferal Zone 16s [Neoarchaediscus The general interval under study spans the Asbian and parvus (Rauzer-Chernoussova) and N. regularis (Suleima- early Brigantian stages and is divided into the B1,B2, and nov)] occur in our bed 40 of the Granite Mountain section P1 Chronozones, with additional subdivisions based prima- (Webster et al. 1984), which would suggest that the base of rily on ammonoid and pelagic bivalve species ranges. Pre- this zone corresponds roughly with the entry of Dombari- cise correlation between the platform carbonate-based type tes (Fig. 11). sections for both the Asbian and Brigantian stages and their basinal, ammonoid-rich counterparts has long been proble- matic (Riley 1993). However, the Asbian-Brigantian Stage Global correlations Boundary is currently designated as the base of the P1b (Poty & Hance 2006, Cozar et al. 2005). Global correlations of the Antler ammonoid faunas are im- The first occurrence of true Girtyoceras in the British peded for a number of reasons: succession occurs at the base of the B2b (Riley 1993), repre- – All of the ammonoid species found in the Antler Fore- sented by such species as G. deani and G. simplex. These land Basin are probably endemic to North America. forms are similar to the North American taxon G. primum – Despite the fact that all Antler Foreland Basin genera and possibly represent an equivalent stage of phylogenetic are cosmopolitan, their stratigraphic ranges are not all con- development. The co-occurrence of G. primum with the cordant with those observed elsewhere. For instance: highest occurring specimens of Entogonites in Utah, how- (1) Goniatites and Entogonites only range concurrently in ever, differs from the situation in North England, because the Rhenish Mountains for a few centimetres. These two Entogonites doesn’t range higher than the upper B1 or B2a genera do co-occur in the Anti-Atlas for a more extended in Great Britain (Riley 1993). interval, but in the Antler Foreland Basin they range to- Our correlation of the G. meslerianum Biozone with the gether through three biozones. (2) In the Antler and Illinois British P1c is based on the position of both of those intervals basins, Kazakhoceras has a much lower stratigraphic oc- below the first appearance of Sulcogirtyoceras. Since both currence than anywhere else. the P1a and P1b are defined in Britain by species of endemic – Some of the Brigantian ammonoid genera from the European goniatites and there are no significant global North Variscides, e.g. Arnsbergites, Hibernicoceras, and ammonoid events in that interval, we cannot confidently Paraglyphioceras have not been recorded from North correlate the Goniatites deceptus-Goniatites eganensis in- America. Furthermore, we are fairly sure that Goniatites terval with any greater precision than P1a–P1b undifferenti- ranges higher stratigraphically in North America than in ated. Europe and that the timing and trends in evolution within The previously mentioned first occurrence of G. bili- clades differ slightly between different global regions. The neatus s.l. in the uppermost Skunk Spring Limestone bed

126 Dieter Korn & Alan L. Titus • Goniatites Zone (middle Mississippian) ammonoids, Nevada and Utah

(Tynan 1980) of Utah is another important datum for lels the Utah association of Calygirtyoceras confusionense global correlation because G. bilineatus s.l. is well docu- with Entogonites borealis. We believe these two assembla- mented to first appear near the base of the Cf6β ges correlate closely in time but are unable to further subdi- foraminiferal zone throughout Western Europe (Conil et vide this interval based on currently available data from al. 1990, Meischner & Nemyrovska 1999, Cozar et al. Africa. The overlying low diversity Goniatites tympanus 2005). That event horizon is now well constrained (Cozar assemblage consists of the nominate taxon associated with et al. 2005) as early Asbian (middle B1) and is remarkably Irinoceras. Goniatites tympanus Korn, Bockwinkel & parsimonious with the ammonoid data from Utah Ebbighausen, 2007 compares very closely to the European (Fig. 11). taxon G. moorei, leaving Korn et al. (2007) to conclude that the Moroccan ammonoid assemblage correlates with Germany (Rhenish Mountains). – The Viséan Kulm facies the upper Asbian (B2) of the British Isles, making it the of north-western Germany contains a rich succession of equivalent of the Calygirtyoceras arcticum interval of ammonoids (Korn 1988, 1990). The ammonoid biostratig- Utah. Overlying the Goniatites tympanus assemblage is a raphy of this region was revised by Korn (1996) and subse- more diverse assemblage containing G. rodioni Korn & quently integrated into a comprehensive relative time scale Ebbighausen, 2006, advanced Calygirtyoceras (C. zriga- correlated with the standard Viséan Series of Belgium and tense Korn & Ebbighausen, 2006), Itimaites, and Proleca- the Asbian and Brigantian stages of England (Korn & nites. The phylogenetic stage of the Calygirtyoceras in this Kaufmann 2009). Although differing in some particulars, assemblage suggest it is equivalent our G. primum or the German zonation can be correlated with the British suc- G. gordoni intervals, most likely the former. cession on a virtual one-to-one basis and many zonal indi- The highest Goniatites interval in Morocco is charac- ces are based on the same taxa. As a result, correlations terized by a low diversity assemblage consisting of three between the German and Great Basin successions are ba- species of the genus (G. stenumbilicatus Kullmann, 1961, sed largely on the same arguments as those made for En- G. gerberi Korn & Ebbighausen, 2006, and G. evelinae gland. We also note that Calygirtyoceras moorei (Nico- Korn & Ebbighausen, 2006). The lack of accessory taxa in laus, 1963), which occurs within the upper portion of the the Moroccan assemblage make precise correlations diffi- Goniatites hudsoni Zone in the Rhenish Mountains, dis- cult, but the species appear to be close phylogenetic equiv- plays morphology suggestive of the stage of development alents of G. multiliratus Gordon (Korn & Ebbighausen in exhibited by girtyoceratids such as C. arcticum. Meis- Klug et al. 2006), G. deceptus sp. nov., and G. eganensis chner & Nemyrovska (1999) document that in the Rhe- sp. nov., leading us to make tentative correlations with that nish Mountains the first occurrence of G. bilineatus,in general interval in the Utah sections. Thus in North Africa the form of the subspecies G. bilineatus romulus, enters (Palaeotethyan) as well as in North America, Goniatites within the top of the Entogonites nasutus Zone, which ar- appears to range stratigraphically higher than in Western gues for an early Asbian (British middle B1) assignment Europe. for the top of the Skunk Spring Limestone Bed and is in complete agreement with all our data from Utah. Palaeontological descriptions North Africa (Anti-Atlas). – Reports of late Viséan ammo- noids from Algeria and Morocco have been made for many Descriptive terminology for conch morphology is patter- years (Delépine 1941), however, only recently has the suc- ned after Korn (2010). Abbreviations of conch dimensions cession been documented in enough detail that relatively (Fig. 13A) are: conch diameter (dm), whorl width (ww), detailed comparisons can be made with Europe and North whorl height (wh), umbilical width (uw = dm1 –wh1 –wh2) America (Korn et al. 1999, 2005, 2007; Klug et al. 2006 and aperture height (ah). The whorl expansion rate and references within). The Tafilalt, particularly the area (WER) is calculated using the algorithm of Korn & Klug 2 2 around the Gara el Itima, has produced a succession of (2007): WER = [dm/(dm – ah)] or (dm1/dm2) . The im- which four assemblages correlate closely with those obser- print zone rate (IZR) characterizes the whorl overlap, and ved in North America. The lowest is characterized by Go- can be calculated by: IZR = (wh–ah)/wh. the terminology niatites lazarus, Maxigoniatites saourensis, Maxigoniati- of the suture lines (Fig. 13B) is taken from Korn et al. tes tafilaltensis; Entogonites saharensis, Bollandoceras (2003a). ergchebbiense, Beyrichoceras elabiodiense, Calygirtyoce- The material described in the following account is held ras darkaouense, and Prolecanites sp., referred to the local in the following collections with the prefixes: UMNH IP – Entogonites-Maxigoniatites Assemblage Zone (Korn et al. Utah Museum of Natural History, Salt Lake City; MB.C. – 2007). In Morocco, the association of Calygirtyoceras dar- Cephalopod collection in the Museum für Naturkunde kaouense, which has a widely evolute, almost cadyconic Berlin; USNM – U.S. National Museum, Washington; juvenile conch, with Entogonites saharensis closely paral- SUI – State University of Iowa, Iowa City.

127 Bulletin of Geosciences • Vol. 86, 1, 2011

A B

Figure 13. A – descriptive terms for the conch morphology of the ammonoids. • B – descriptive terms for the suture lines of the ammonoids de- scribed here.

Order Goniatitida Hyatt, 1884 Genus Bollandoceras Bisat, 1952 Suborder Goniatitina Hyatt, 1884 Superfamily Pericyclaceae Hyatt, 1900 Type species. – Beyrichoceras submicronotum Bisat, 1934 (original designation); subjective junior synonym of Bol- Included families. – Pericyclidae Hyatt, 1900; Muenstero- landoceras micronotum (Phillips, 1836). ceratidae Librovitch, 1957; Intoceratidae Kusina, 1971; Maxigoniatitidae Korn, Klug & Mapes, 1999; Entogoniti- Genus definition. – Maxigoniatitins with moderate to ma- dae Ruzhencev & Bogoslovskaya, 1971. jor ontogenetic changes of conch morphology; adult conch discoidal (ww/dm = 0.35–0.45) with rapidly expanding Family Maxigoniatitidae Korn, Klug & Mapes, 1999 whorls (WER above 2.10 in stages larger than 10 mm conch diameter); umbilicus moderately wide to wide Included subfamilies. – Maxigoniatitinae Korn, Klug & (uw/dm = 0.40–0.50) in juveniles and narrow or almost Mapes, 1999; Dzhaprakoceratinae Korn, Bockwinkel & closed in the adult stage. Shell ornament consisting of fine Ebbighausen, 2010; Bollanditinae Bockwinkel, Korn & biconvex growth lines with a rather deep ventral sinus; ste- Ebbighausen, 2010. inkern often with constrictions parallel to the growth lines. Suture line with very narrow to narrow, V-shaped external Subfamily Maxigoniatitinae Korn, Klug & Mapes, 1999 lobe with gently sinuous, slightly diverging flanks; secon- dary prongs of the external lobe hook-shaped; median sad- Subfamily definition. – Maxigoniatitidae with a subevo- dle very low or low; ventrolateral saddle usually broadly lute or evolute (uw/dm = 0.35–0.55) juvenile stage with rounded; adventive lobe V-shaped, often much shallower weakly or moderately depressed whorl cross section. Or- than the external lobe. nament usually with biconvex, fine growth lines and spi- ral lines in some genera. Suture line with V-shaped exter- Included species. – aridum: Bollandoceras aridum Bock- nal lobe, flanks of the external lobe usually strongly winkel, Korn & Ebbighausen, 2010, p. 233; Gourara, Alge- sinuous. ria; bashatchense: Bollandites bashatchensis Popov, 1968, p. 38; Tien Shan; bellmanense: Dzhaprakoceras bellma- Included genera. – Benimehlalites Bockwinkel, Korn & nense Riley, 1996, p. 51; Lancashire; boreus: Bollandites Ebbighausen, 2010; Beyrichoceras Foord, 1903; Bollan- boreus Kusina, 1980, p. 60; North Urals; crowdecotense: doceras Bisat, 1952; Maxigoniatites Korn, Klug & Mapes, Bollandoceras crowdecotense Korn & Tilsley, 2006, 1999; Pachybollandoceras Bockwinkel, Korn & Ebbig- p. 131; Derbyshire; fordi: Bollandoceras fordi Korn & Til- hausen, 2010. sley, 2006, p. 127; Derbyshire; furiense: Bollandoceras

128 Dieter Korn & Alan L. Titus • Goniatites Zone (middle Mississippian) ammonoids, Nevada and Utah

A B

Figure 14. Bollandoceras occidentale sp. nov. from bed 6 (sample 05UTMI-3) of Middle Confusion Range 1. • A – holotype UMNH IP 2630; × 4.0. • B – paratype UMNH IP 2631; × 5.0.

Table 1. Conch ontogeny (Fig. 15) of Bollandoceras occidentale sp. nov. dm conch shape whorl cross section shape aperture 2 mm thinly pachyconic; evolute strongly depressed; moderately embracing (ww/wh ~ 2.20; low (WER ~ 1.60) (ww/dm ~ 0.60; uw/dm ~ 0.50) IZR ~ 0.23) 10 mm thickly discoidal; involute weakly compressed; very strongly embracing (ww/wh ~ 0.95; moderate (WER = 1.75–1.90) (ww/dm = 0.50–0.55; uw/dm = 0.05–0.10) IZR ~ 0.55) 25 mm thinly discoidal; involute weakly compressed; very strongly embracing (ww/wh ~ 0.70; moderate (WER ~ 1.80) (ww/dm ~ 0.40; uw/dm ~ 0.01) IZR ~ 0.55) furiense Padget, 1952, p. 864; Ireland; globosum: Bollan- tianshanicum Popov, 1968, p. 44; Tien Shan; undulatum: doceras globosum Bisat, 1952, p. 177; Yorkshire; hodde- Dzhaprakoceras undulatum Riley, 1996, p. 66; Lancashire; rense: Beyrichoceras hodderense Bisat, 1924, p. 84; Lan- westheadi: Dzhaprakoceras westheadi Riley, 1996, p. 66; cashire; inopinum: Bollandoceras inopinum Ruzhencev, Lancashire; zuhara: Bollandoceras zuhara Bockwinkel, 1975, p. 39; Verkhoyan; kaindynense: Bollandites? kain- Korn & Ebbighausen, 2010, p. 235; Gourara, Algeria. dynense Popov, 1968, p. 40; Tien Shan; librovitchi: Beyri- choceras librovitchi Popov, 1968, p. 43; Tien Shan; mac- kellari: Beyrichoceras mackellari Campbell, Brown & Bollandoceras occidentale sp. nov. Coleman, 1983, p. 89; Queensland; micronotoide: Bollan- Figures 14, 15 doceras micronotoides Bisat, 1934, p. 290; Yorkshire; micronotum: Goniatites micronotus Phillips, 1836, p. 234; Derivation of name. – After occidens = the West; because Yorkshire; minusculum: Dzhaprakoceras? minusculum of its occurrence in western North America. Kusina, 1980, p. 55; North Urals; mirrih: Bollandoceras mirrih Bockwinkel, Korn & Ebbighausen, 2010, p. 237; Holotype. – Specimen UMNH IP 2630, illustrated in Fig. 14A. Gourara, Algeria; nitens: Bollandoceras nitens Bockwin- kel, Korn & Ebbighausen, 2010, p. 227; Gourara, Algeria; Type locality and horizon. – Middle Confusion Range 1, occidentale: Bollandoceras occidentale sp. nov.; Antler bed 10 (sample 05UTMI-3); Camp Canyon Member of Foreland Basin; parvum: Bollandoceras parvum Kusina, Chainman Formation, Calygirtyoceras arcticum Ammo- 1994, p. 166; Mongolia; politum: Bollandoceras politum noid Biozone. Bockwinkel, Korn & Ebbighausen, 2010, p. 231; Gourara, Algeria; stylense: Bollandoceras stylense Kusina, 1991, Material. – Besides the holotype, four paratypes from the p. 40; Donets Basin; subangulare: Bollandoceras subangu- type sample and one from bed 17 (sample 07UTJU-1) of lare Bockwinkel, Korn & Ebbighausen, 2010, p. 229; Gou- Granite Mountain-South. The size of the specimens ranges rara, Algeria; submicronotum: Bollandoceras submicrono- from 10 to 25 mm conch diameter. tum Bisat, 1934, p. 291; Derbyshire [synonym of B. micronotum]; suursureni: Bollandoceras suursureni Ku- Diagnosis. – Species of Bollandoceras with thinly pachy- sina, 1994, p. 167; Mongolia; tianshanicum: Beyrichoceras conic conch in juvenile stages (ww/dm 0.60–0.70 up to

129 Bulletin of Geosciences • Vol. 86, 1, 2011

D

C

E

B

A

Figure 15. Bollandoceras occidentale sp. nov. from bed 6 (sample 05UTMI-3) of Middle Confusion Range 1. • A – cross section of paratype UMNH IP 2632; × 2.5. • B – constriction course of holotype UMNH IP 2630, at 13.2 mm diameter, 6.4 mm ww, 6.5 mm wh; × 4.0. • C – suture line of holotype UMNH IP 2630, at 13.6 mm diameter, 6.6 mm ww, 6.8 mm wh; × 6.0. • D, E – ontogenetic development of the conch width index (ww/dm), umbilical width index (uw/dm), and whorl expansion rate (WER) of all available specimens.

Table 2. Conch dimensions (in mm) and proportions for reference specimens of Bollandoceras occidentale sp. nov.

dm ww wh uw ah ww/dm ww/wh uw/dm WER IZR PT UMNH IP 2632 24.5 9.8 14.0 0.2 6.1 0.40 0.70 0.01 1.78 0.56 HT UMNH IP 2630 14.7 6.5 8.2 0.9 4.2 0.44 0.80 0.06 1.95 0.49 PT UMNH IP 2635 11.3 5.6 6.3 0.7 – 0.49 0.88 0.06 – – PT UMNH IP 2631 9.8 5.1 5.2 0.6 2.6 0.52 0.98 0.06 1.88 0.49

6 mm diameter); relative conch width decreasing during depressed whorl cross section to the narrowly umbilicate ontogeny to 0.40 at a diameter of 25 mm. Umbilicus relati- adult conch with laterally compressed whorls (Fig. 15A). vely widest at 2–3 mm diameter (uw/dm = 0.40–0.50), be- In all stages during ontogeny, the flanks and umbilical wall coming almost closed at 20 mm. Whorl expansion rate low are rounded, and the conch is thickest in some distance in juveniles (WER 1.60), increasing to more than 1.80 at from the umbilicus. The adult stage shows modification of more than 10 mm diameter. Ornament of biconvex, very the venter; it becomes slightly flattened with the outer fine growth lines; steinkern with faint, slightly biconvex flanks appearing truncated. constrictions. Suture with inflexed, slightly diverging The best-preserved specimen is holotype UMNH IP flanks of the external lobe. 2630 (Fig. 14A); it is fully chambered and almost 15 mm in diameter. It is discoidal (ww/dm = 0.44) with an almost Description. – The cross section of paratype UMNH IP closed umbilicus (uw/dm = 0.06) and a moderately high 2632 and the morphometric plots demonstrate the conspi- aperture (WER = 1.95). The conch is thickest on the flanks, cuous ontogenetic changes during ontogeny (Fig. 15D, E). away from the umbilicus, and the venter is narrowly The umbilicus is wide in the juvenile stage, reaching a rounded. Shell remains are preserved only in a small area uw/dm ratio of 0.50 at 2 mm conch diameter. By 15 mm near the aperture; they show extremely fine growth lines. diameter, the umbilicus is almost closed. The conch width The internal mould has three constrictions standing in ir- ratio is highest at 3 mm diameter (ww/dm = 0.70) and the- regular distances of less than 120°. They extend in linear reafter decreases continuously to a value of 0.40 at 24 mm course over the flanks, bend forward to form a low diameter. Stages above 6 mm diameter have a moderately ventrolateral projection and then reverse into a moderately high aperture, resulting in a whorl expansion rate of deep ventral sinus (Fig. 15B). 1.80–1.95. The suture line of paratype UMNH IP 2630 is typical Paratype UMNH IP 2632 clearly shows the transforma- for the genus with an external lobe that has sinuous, diverg- tion from widely umbilicate juvenile forms with a ventrally ing flanks and a median saddle of one third of the height of

130 Dieter Korn & Alan L. Titus • Goniatites Zone (middle Mississippian) ammonoids, Nevada and Utah

Figure 16. Entogonites burbankensis sp. nov.•A–holotype UMNH IP 2637 from bed 4 (sample 01UTMI-2) of South Burbank Hills; × 6.0.•B–paratype UMNH IP 2638 from bed 4 (sample 01UTMI-2) of South Burbank Hills; × 6.0.

A B the external lobe depth (Fig. 15C). The ventrolateral saddle and rounded adventive lobe of the suture line (e.g. Ruzhen- is broadly rounded, and the adventive lobe asymmetric cev & Bogoslovskaya 1971). with a markedly more sinuous dorsal flank. The new Družetić (north-western Serbia) genus Ubites Korn and Sudar 2010 possesses Entogonites-like orna- Discussion. – Bollandoceras is a rare genus on the American ment, but an evolute ribbed juvenile stage and later closure continent. Gordon (1957) reported “Beyrichoceras micro- of the umbilicus (similar to Bollandites). This strongly sug- notum” from Kiruktagiak River in Alaska that co-occurs gests that Entogonites is more closely connected phylogen- with the genus Goniatites. These specimens resemble B. oc- etically to other Early Carboniferous ammonoids such as cidentale in their general form, but differ in the wider exter- pericylids, girtyoceratids, or Bollandites, rather than nal lobe, the lower aperture (WER = 1.70 at 18 mm diame- Nomismoceras (Korn & Sudar in Korn et al., 2010). The ter), and the much wider umbilicus (uw/dm = 0.07). family Entogonitidae is therefore placed in the superfamily Bollandoceras is most diverse in North England, Mo- Pericyclaceae. rocco, Algeria, and the Tien Shan, where a number of spe- cies are known (Bisat 1952; Riley 1996; Korn & Tilsley 2006; Korn et al. 1999, 2007; Bockwinkel et al. 2010; Genus Entogonites Kittl, 1904 Popov 1968). All of the species from these regions, how- ever, differ from B. occidentale by having wider umbilici Type species. – Tetragonites Grimmeri Kittl, 1904 (by mo- (uw/dm larger than 0.10) at 20 mm conch diameter and notypy). higher apertures. The most common species from North England, Bollandoceras micronotum (Phillips, 1836), for Genus definition. – As for the family. instance, has at 20 mm conch diameter, an umbilical width of 0.10, and a whorl expansion rate over 2.00. Included species. – acus: Entogonites acus sp. nov.; Antler Foreland Basin; borealis: Entogonites borealis Gordon, 1957, p. 53; Alaska; burbankensis: Entogonites burban- Family Entogonitidae Ruzhencev & Bogoslovskaya, 1971 kensis sp. nov.; Antler Foreland Basin; grimmeri: Tetrago- nites Grimmeri Kittl, 1904, p. 677; Bosnia; nasutus: Peri- Family definition. – Pericyclaceae with strong radial orna- cyclus nasutus Schmidt, 1941, p. 151; Harz; saharensis: ment consisting of sharp ribs, which frequently dichoto- Entogonites saharensis Korn, Klug & Mapes, 2005, p. 363; mize. Inner whorls usually tetrangularly coiled. Anti-Atlas; tetragonus: Branneroceratoides tetragonus Kullmann, 1962, p. 88; Serbia. Included genera. – Entogonites Kittl, 1904; Tetragonites Kittl, 1904 [homonym of Tetragonites Kossmat, 1895; syno- nym of Entogonites Kittl, 1904]; Kittliella Frech, 1906 [syno- Entogonites burbankensis sp. nov. nym of Entogonites Kittl, 1904]; Ubites Korn & Sudar, 2010. Figures 16, 17A

Discussion. – Entogonites is still an enigmatic genus and Derivation of name. – After the South Burbank Hills, the its phylogenetic relationships are not solved. Traditionally, type locality. the genus has been placed phylogenetically near Nomismo- ceras based on its thinly discoidal, relatively widely umbi- Holotype. – Specimen UMNH IP 2637, illustrated in licate conch, ornament with high ventrolateral projection, Fig. 16A.

131 Bulletin of Geosciences • Vol. 86, 1, 2011

Table 3. Conch dimensions (in mm) and proportions for reference specimens of Entogonites burbankensis sp. nov.

dm ww wh uw ah ww/dm ww/wh uw/dm WER IZR HT UMNH IP 2637 8.7 3.3 3.9 2.5 2.8 0.38 0.83 0.28 2.18 0.29 PT UMNH IP 2638 7.3 3.1 3.7 2.0 2.3 0.42 0.84 0.28 2.12 0.38 PT UMNH IP 2639 6.2 2.7 2.9 2.0 – 0.43 0.93 0.32 – –

E

C

F

B

D A

Figure 17. Species of Entogonites.•A–Entogonites burbankensis sp. nov., suture line of paratype UMNH IP 2638 from bed 4 (sample 01UTMI-2) of South Burbank Hills, at 6.3 mm diameter, 2.8 mm ww, 3.2 mm wh; × 10.•B–Entogonites borealis Gordon, 1957, suture line of specimen UMNH IP 2642 from bed 7 (sample 93UTMI-25) of Jensen Wash, at 4.5 mm ww, 4.6 mm wh; × 10.•C–Entogonites acus sp. nov., suture line of holotype UMNH IP 2658 from a single bullion of South Needle Range, at 3.5 mm diameter, 3.9 mm ww, 3.2 mm wh; × 10.•D–Entogonites acus sp. nov., cross section of paratype UMNH IP 2662 from bed 8 (sample 07UTMI-6) of South Burbank Hills; × 3. • E, F – Entogonites acus sp. nov., ontogenetic development of the conch width index (ww/dm), umbilical width index (uw/dm), and whorl expansion rate (WER) of all available specimens.

Type locality and horizon. – South Burbank Hills, bed 4; can be seen through the umbilicus and are weakly tetran- Camp Canyon Member of Chainman Formation, Calygir- gular. The ornament is dominated by approximately 45 tyoceras arcticum Biozone. prominent ribs on the last volution. These extend radially across the flanks and bend forward to form a moderately Material. – The holotype and three paratypes; conch dia- high ventrolateral projection and inflex into a deep ven- meter up to 9 mm. tral sinus. The ribs dichotomize in the ventrolateral area, becoming weaker across the venter. A single constriction Diagnosis. – Species with a thinly discoidal conch (ww/dm of the internal mould can be seen at the beginning of the = 0.35–0.40), moderate umbilicus (uw/dm = 0.28–0.32) last whorl; it is particularly deep on the venter and follows and narrowly rounded venter at 8 mm conch diameter. the course of the ribs. Aperture moderately high (WER = 2.10–2.20). Inner Paratype UMNH IP 2638 is little more than 6 mm in di- whorls with weak tetrangular coiling. Shell ornament of ameter and has a morphology very similar to the holotype. weak, rounded and ventrolaterally dichotomising ribs. It has only 35 ribs, which are sharp and dichotomize in the Ventrolateral projection of ribs moderately high, ventral si- ventrolateral area. The ventral sinus of the ribs is chev- nus deep. Suture line with asymmetric ventrolateral saddle. ron-shaped in this specimen. The specimen has two steinkern constrictions on the first half of the last whorl Description. – Of the well-preserved material, holotype (Fig. 16B). UMNH IP 2637 is the largest at slightly less than 9 mm The suture line of paratype UMNH IP 2638 has, at 6 diameter (Fig. 16A). The shape is discoidal (ww/dm = mm conch diameter, an external lobe with slightly curved, 0.38), with a moderate umbilicus (uw/dm = 0.28), and a subparallel and weakly diverging flanks and a median sad- moderately high aperture (WER = 2.18). The whorl cross dle of about one quarter height of the external lobe depth section is laterally compressed with a rounded umbilical (Fig. 17A). The broadly rounded ventrolateral saddle is margin and a narrowly rounded venter. The inner whorls asymmetric with a steep external and an oblique lateral

132 Dieter Korn & Alan L. Titus • Goniatites Zone (middle Mississippian) ammonoids, Nevada and Utah

Figure 18. Entogonites borealis Gor- don, 1957 from bed 7 (sample 93UTMI-25) of Jensen Wash. • A – spe- cimen UMNH IP 2644; × 3.0.•B–spec- imen UMNH IP 2645; × 3.0.

A B

Table 4. Conch dimensions (in mm) and proportions for reference specimens of Entogonites borealis Gordon, 1957.

dm ww wh uw ah ww/dm ww/wh uw/dm WER IZR PT UMNH IP 2644 16.7 5.8 6.3 5.9 4.8 0.35 0.92 0.35 1.97 0.24 HT UMNH IP 2645 15.7 5.5 5.8 5.2 4.3 0.35 0.95 0.33 1.87 0.27 PT UMNH IP 2642 14.1 5.4 5.4 5.0 – 0.39 1.01 0.35 – – PT UMNH IP 2646 12.0 4.1 4.0 4.1 3.2 0.34 1.02 0.34 1.84 0.21 flank, the latter belonging to a small, slightly asymmetric ture moderately high in the adult stage (WER = 1.85–2.00). adventive lobe. Inner whorls with very weak tetrangular coiling. Shell or- nament with weak, sharp, ventrolaterally-dichotomizing Discussion. – Entogonites nasutus and E. borealis have nar- ribs. Ventrolateral projection of ribs high, ventral sinus row umbilici and are close to E. burbankensis. Both are, deep. Suture line with symmetric ventrolateral saddle. however, more widely umbilicate than E. burbankensis; their uw/dm ratio is about 0.35 (measured in the holotype Description. – Specimen UMNH IP 2645 is a well- of E. borealis), in contrast to E. burbankensis, where, at preserved steinkern nearly 16 mm in diameter (Fig. 18A). 7–8 mm conch diameter, the uw/dm ratio is around 0.30. It is thinly discoidal (ww/dm = 0.35) with a moderately Furthermore, the ribs of E. burbankensis show a much wide umbilicus (uw/dm = 0.33). The inner whorls show a more pronounced ventrolateral projection than E. nasutus very weak tetrangular coiling. The last whorl possesses 36 and E. borealis. sharp ribs, which regularly bifurcate in the outer flank area. The dichotomizing ribs extend almost straight across the flanks, and it is particularly the apertural of the two bran- Entogonites borealis Gordon, 1957 ches that forms a ventrolateral projection. The ventral sinus Figures 17B, 18 of the ribs is deep. A slightly larger specimen, UMNH IP 2644 (17 mm di- 1957 Entogonites borealis Gordon, p. 53, pl. 6, figs 37–40. ameter), is similar, having the same weakly developed tetrangular coiling of the inner whorls and umbilical width Holotype. – Specimen USNM 118981, illustrated by Gor- ratio (uw/dm = 0.35). It has nearly 40 ribs, which show, on don (1957) on pl. 6, figs 37–40. the first half of the last volution, a moderately high ventrolateral projection (Fig. 18B). At the largest pre- Type locality and horizon. – USGS locality 10864, Kiruk- served diameter, this projection is almost as high as in the tagiak River (Brooks Range); Kuna Formation, probably larger specimen UMNH IP 2654. Calygirtyoceras arcticum Biozone. The suture line was drawn from specimen UMNH IP 2642 at approximately 11 mm diameter (Fig. 17B). It is Material. – Fourteen specimens; conch diameter up to characteristic for the genus with an almost parallel-sided 17 mm. external lobe, a broadly rounded ventrolateral saddle, and a small, almost symmetric, V-shaped adventive lobe. Diagnosis. – Entogonites with thinly discoidal conchs (ww/dm = 0.35–0.40) and moderately wide umbilici Discussion. – Entogonites nasutus (Schmidt, 1941) is simi- (uw/dm = 0.30–0.35) at 12–17 mm conch diameter. Aper- lar in conch proportions and degree of tetrangular coiling,

133 Bulletin of Geosciences • Vol. 86, 1, 2011

Figure 19. Entogonites acus sp.nov.•A–para- type UMNH IP 2654 from bed 13 (sample 97UTMI-12) of Jensen Wash; × 3.0.•B–holo- type UMNH IP 2658 from a single bullion of South Needle Range; × 3.0.•C–paratype UMNH IP 2655 from bed 25 (sample 05UTJU-12) of Granite Mountain South; × 3.0.

A

BC but has a much lower, more broadly rounded ventrolateral Diagnosis. – Species of Entogonites with a thinly discoidal projection of the ribs. E. grimmeri (Kittl, 1904) and E. saha- conch (ww/dm = 0.25–0.30), moderately wide umbilicus rensis Korn, Klug & Mapes, 1999 have a similar conch and (uw/dm = 0.40–0.45) at 12–22 mm conch diameter, and a rib morphology, but possess conspicuous tetrangular coiling slightly flattened venter. Aperture moderately high (WER of the inner whorls. E. acus from the Chainman Formation = 1.75–1.90). Inner whorls with very weak tetrangular coi- has a wider umbilicus (uw/dm = 0.40–0.45) and a flattened ling. Shell ornament with weak, sharp and ventrolaterally venter, it is thus clearly separated from E. borealis. dichotomising ribs. Ventrolateral projection of ribs high, ventral sinus deep. Suture line with asymmetric ventrolate- ral saddle. Entogonites acus sp. nov. Figures 17C–F, 19 Description. – The cross section of paratype UMNH IP 2662 displays the minor ontogenetic changes in conch pro- Derivation of name. – After Lat. acus = needle, reference to portions; the ww/dm ratio decreases from 0.57 at 1 mm dia- the type locality. meter to 0.26 at 21 mm, the uw/dm ratio ranges between 0.40 and 0.45 throughout ontogeny, and the whorl expan- Holotype. – Specimen UMNH IP 2658, illustrated in sion rate is between 1.70 and 2.00 (Fig. 17D). More conspi- Fig. 19A. cuous are the changes in the shape of the whorl cross sec- tion. They are circular up to 3 mm conch diameter, then Type locality and horizon. – Needle Range, single bullion becoming laterally compressed, and followed by the adult (07UTMI-10); Camp Canyon Member of Chainman For- stage (above 12 mm diameter), in which the flanks and, on mation, probably Girtyoceras primum Biozone. the last volution, also the venter become flattened. The largest specimen is paratype UMNH IP 2654; it Material. – The holotype and eight paratypes; conch dia- measures nearly 22 mm and is slightly deformed by a cal- meter up to 22 mm. cite-filled fissure. It is almost entirely testiferous

134 Dieter Korn & Alan L. Titus • Goniatites Zone (middle Mississippian) ammonoids, Nevada and Utah

Table 5. Conch dimensions (in mm) and proportions for reference specimens of Entogonites acus sp. nov.

dm ww wh uw ah ww/dm ww/wh uw/dm WER IZR PT UMNH IP 2654 21.7 5.5 6.9 9.6 5.5 0.25 0.80 0.44 1.79 0.21 HT UMNH IP 2657 21.2 5.4 7.2 9.3 5.6 0.26 0.76 0.44 1.86 0.21 PT UMNH IP 2662 21.1 5.5 6.5 9.5 5.3 0.26 0.85 0.45 1.78 0.18 PT UMNH IP 2658 17.2 4.8 5.5 7.5 4.6 0.28 0.87 0.44 1.85 0.17 PT UMNH IP 2656 13.9 4.0 4.7 6.2 3.8 0.29 0.86 0.44 1.88 0.20 PT UMNH IP 2655 13.0 3.6 4.5 5.4 3.5 0.27 0.78 0.42 1.89 0.22

(Fig. 18A). The conch is lenticular (ww/dm = 0.25) with a dily differentiated from most other species of Entogonites. moderately wide umbilicus (uw/dm = 0.44) and a rather In addition to the ventral morphology, E. acus also has a low aperture (WER = 1.79). The flanks are slightly flat- wider umbilicus than the other two Chainman Formation tened and converge slowly towards the rounded venter. species (uw/dm = 0.40–0.45 in E. acus, 0.35 in E. borealis, The umbilical wall is oblique, and the umbilical margin 0.28–0.32 in E. burbankensis). A paratype of E. borealis fi- rounded. The inner whorls are not well-preserved in the gured by Gordon (1957, pl. 6, figs 34–36) is in its conch specimen, but they show that only very weak tetrangular shape similar to E. acus. However, the Alaskan specimen is coiling is present. About 40 sharp ribs can be counted on a 13 mm diameter internal mould with a wide umbilicus the last volution; these ribs have regular distances, and only (uw/dm = 0.53) and strong constrictions and can thus be in a small zone at the end of growth, crowding of some excluded from E. acus (uw/dm = 0.42 at 13 mm diameter). weaker ribs can be seen. The ribs extend from the umbili- It may represent a new species. cus slightly rursiradiate and pass over the flanks almost rectilinearly. In the ventrolateral position, they turn almost rectangularly forward to form a prominent, narrow projec- Superfamily Girtyocerataceae Wedekind, 1918 tion, and regularly dichotomize. On the venter, they form a sinus twice as deep as the height of the ventrolateral sa- Included families. – Girtyoceratidae Wedekind, 1918; Basch- lient; this sinus is very narrow and chevron-shaped. kiritidae Ruzhencev, 1960. The holotype (UMNH IP 2658) is the best-preserved individual (Fig. 19A). It has a diameter of 17 mm and is Family Girtyoceratidae Wedekind, 1918 thinly discoidal (ww/dm = 0.28), with a moderately wide umbilicus (uw/dm = 0.44) and a rather low aperture (WER Family definition. – Girtyocerataceae with ontogenetically = 1.85). The flanks are convexly rounded and separated changing conch shape; inner whorls evolute, umbilicus from the flat venter by a distinct ventrolateral margin. At closing during ontogeny, adult stage often discoidal and least two of the inner whorls show tetrangular coiling. The oxyconic. Ornament with biconvex growth lines. Suture ornament of the last volution consists of 35 sharp ribs. line with V-shaped external lobe and rounded ventrolateral These extend slightly retrosiradiate across the flanks and saddle; adventive lobe V-shaped with slightly sinuous turn on the outer flank forward to form a narrow and high flanks. salient. The ventral sinus is deep and subangular. Rib split- ting is regular and occurs at the beginning of the Included genera. – Calygirtyoceras Korn, Klug & Ma- ventrolateral projection. pes, 1999; Cousteauceras Korn, 1988; Edmooroceras A larger paratype, UMNH IP 2654 (22 mm diameter; Elias, 1956; Eumorphoceras Girty, 1909; Girtyoceras Fig. 19A), as well as the smaller specimens UMNH IP Wedekind, 1918; Peytonoceras Saunders, 1966; Sulco- 2656 (14 mm diameter) and UMNH IP 2655 (13 mm diam- girtyoceras Ruzhencev, 1960; Sundernites Korn, 1993; eter) closely resemble the conch morphology of the Torulites Kusina & Yatskov, 1987; Tumulites McCaleb, holotype. Quinn & Furnish, 1964; Zhongningoceras Yang, 1986; The suture line of the holotype (UMNH IP 2658) has an Adelphoceras Girty, 1909 [non Adelphoceras Barrande, external lobe with subparallel, slightly curved flanks and a 1870; synonym of Girtyoceras Wedekind, 1918]; Dryo- median saddle of about 25 per cent of the external lobe choceras Morgan, 1924; [synonym of Girtyoceras We- depth (Fig. 17C). The ventrolateral saddle is slightly asym- dekind, 1918]; Jeminayceras Wang, 1983 [synonym of metric and broadly rounded, and the small adventive lobe Girtyoceras Wedekind, 1918]; Medioloboceras Kull- is V-shaped. mann, 1962 [synonym of Eumorphoceras Girty, 1909]; Sagittoceras Hind, 1918 [synonym of Girtyoceras We- Discussion. – E. acus has a flat venter and thus can be rea- dekind, 1918].

135 Bulletin of Geosciences • Vol. 86, 1, 2011

B

A

D

C E

Figure 20. Calygirtyoceras confusionense sp.nov.•A–holotype MB.C.12001.1 from bed 9 of Middle Confusion Range 2; × 1.0.•B–paratype MB.C.12001.2 from bed 9 of Middle Confusion Range 2; × 1.5.•C–paratype UMNH IP 2692 from bed 17 (sample 94UTJU-1) of Granite Mountain South; × 1.5.•D–paratype UMNH IP 2690 from bed 7 (sample 93UTMI-25) of Jensen Wash; × 2.5.•E–paratype UMNH IP 2689 from bed 7 (sample 93UTMI-25) of Jensen Wash; × 2.5.

Genus Calygirtyoceras Korn, Klug & Mapes, 1999 confusionense sp. nov.; Antler Foreland Basin; darkaoua- ense: Calygirtyoceras darkaouaense Korn, Klug & Mapes, Type species. – Calygirtyoceras darkaouaense Korn, Klug 1999, p. 354; Anti-Atlas; moorei: Girtyoceras moorei Ni- & Mapes, 1999 (original designation). colaus, 1963, p. 118; Rhenish Mountains; platyforme: Gir- tyoceras platyforme Moore, 1946, p. 403; Yorkshire; zri- Genus definition. – Girtyoceratidae with moderately large gatense: Calygirtyoceras zrigatense Korn & Ebbighausen, conch that during ontogeny passes through very different 2006, p. 16; Anti-Atlas. morphological stages: early juveniles are widely umbilicate with trapezoidal whorl cross sections, later barrel-shaped with a sharp umbilical margin; intermediate stage with roun- Calygirtyoceras confusionense sp. nov. ded flanks and venter; adult stage lenticular-oxyconic. Figures 20, 21 Lacks ventrolateral grooves. Suture line with V-shaped ex- ternal lobe, moderately high median saddle, broadly roun- Derivation of name. – After the Confusion range, type re- ded ventrolateral saddle, and V-shaped adventive lobe. gion of the species.

Included species. – arcticum: Girtyoceras arcticum Gor- Holotype. – Specimen MB.C.12001.1, illustrated in don, 1957, p. 50; Alaska; confusionense: Calygirtyoceras Fig. 20A.

136 Dieter Korn & Alan L. Titus • Goniatites Zone (middle Mississippian) ammonoids, Nevada and Utah

E

F

D G

C

B

A

Figure 21. Calygirtyoceras confusionense sp.nov.•A–suture line of holotype MB.C.12001.1 from bed 9 of Middle Confusion Range 2, at 40.0 mm diameter, 21.9 mm ww, 18.5 mm wh; × 4.0.•B–constriction course of paratype MB.C.12001.2 from bed 9 of Middle Confusion Range 2, at 22.0 mm di- ameter, 16.2 mm ww, 8.7 mm wh; × 5.0. • C – cross section of paratype MB.C.12000 from bed 6 of Middle Confusion Range 1; × 2.5. • D – cross section of paratype UMNH IP 2693 from bed 17 (sample 94UTJU-1) of Granite Mountain South; × 2.5. • E–G – ontogenetic development of the conch width in- dex (ww/dm), umbilical width index (uw/dm), whorl width index (ww/wh), and whorl expansion rate (WER) of all available specimens.

Type locality and horizon. – Middle Confusion Range 2, 0.60–0.70; uw/dm = 0.35–0.40), and a discoidal, narrowly bed 9; Camp Canyon Member of Chainman Formation, umbilicate conch at 50–60 mm diameter (ww/dm = 0.45; Calygirtyoceras confusionense Biozone. uw/dm = 0.15). Whorl cross section with conspicuous on- togenetic changes, crescent-shaped in the early juveniles, Material. – The holotype and 38 paratypes; conch diameter later subtrapezoidal with pronounced ventrolateral margin up to 59 mm. and flat or concave venter (2–6 mm diameter), followed by an intermediate stage with rounded venter and angular um- Diagnosis. – Species of Calygirtyoceras with a thickly pa- bilical margin (10–20 mm diameter), a preadult stage with chyconic, widely umbilicate conch at 6–8 mm diameter laterally compressed whorls and a tectiform venter (ww/dm = 0.80; uw/dm = 0.60–0.65), a thinly pachyconic, (30–40 mm diameter), and an adult oxyconic stage (50 mm moderately umbilicate conch at 20 mm diameter (ww/dm = diameter). Ornamented with lamellose prorsiradiate

137 Bulletin of Geosciences • Vol. 86, 1, 2011

Table 6. Conch ontogeny (Fig. 21) of Calygirtyoceras confusionense sp. nov. dm conch shape whorl cross section shape aperture 1.5 mm thickly pachyconic; subevolute strongly depressed; moderately embracing (ww/wh ~ 2.35; moderate (WER ~ 1.80) (ww/dm ~ 0.75; uw/dm ~ 0.40) IZR ~ 0.20) 5 mm thickly pachyconic; very evolute extremely depressed; moderately embracing (ww/wh = 3.50–4.00; low (WER ~ 1.50) (ww/dm = 0.75–0.80; uw/dm = 0.60–0.65) IZR ~ 0.15) 10 mm thickly pachyconic; evolute extremely depressed; moderately embracing (ww/wh = 2.80–3.00; low (WER = 1.60–1.65) (ww/dm = 0.80–0.85; uw/dm = 0.50–0.55) IZR ~ 0.20) 25 mm thinly pachyconic; subevolute weakly depressed; strongly embracing (ww/wh ~ 1.50; IZR ~ 0.38) moderate (WER ~ 1.80) (ww/dm ~ 0.62; uw/dm ~ 0.32) 55 mm thickly discoidal; subinvolute weakly compressed; strongly embracing (ww/wh ~ 0.90; high (WER ~ 2.15) (ww/dm ~ 0.55; uw/dm ~ 0.16) IZR ~ 0.36)

Table 7. Conch dimensions (in mm) and proportions for reference specimens of Calygirtyoceras confusionense sp. nov.

dm ww wh uw ah ww/dm ww/wh uw/dm WER IZR HT MB.C.12001.1 58.8 25.8 29.5 8.1 18.9 0.44 0.87 0.14 2.17 0.36 PT MB.C.12000 37.3 19.9 17.7 8.3 10.1 0.53 1.12 0.22 1.88 0.43 PT UMNH IP 2692 31.1 17.5 14.1 7.7 8.1 0.56 1.24 0.25 1.83 0.43 PT UMNH IP 2693 30.3 16.5 14.8 6.4 8.8 0.54 1.11 0.21 1.99 0.40 PT MB.C.12001.2 29.9 18.3 13.6 7.5 8.2 0.61 1.34 0.25 1.90 0.40 PT UMNH IP 2690 18.0 11.5 7.5 6.3 4.4 0.64 1.54 0.35 1.77 0.40 PT UMNH IP 2689 13.3 10.2 5.3 6.6 3.0 0.77 1.92 0.50 1.65 0.44 growth lines and faint umbilical ribs in juveniles; later sta- venter is already acute by half a whorl earlier (at 40 mm di- ges with fine slightly biconvex growth lines. Shell con- ameter), but the whorl cross section is tectiform. Another strictions in intermediate growth stages. half whorl earlier, i.e. at the beginning of the last preserved whorl, the venter is slightly angular. The conch is widest at Description. – The biometric plots show that the species the slightly angular umbilical margin, and the umbilical undergoes significant ontogenetic changes (Fig. 21E–G) in wall is steep. The suture line of the holotype shows a the conch width ratio, the umbilical width ratio, and the Y-shaped external lobe with very narrow, lanceolate sec- whorl expansion rate, which do not correlate with each ot- ondary prongs and a median saddle that reaches almost half her. Intraspecific variability appears to be rather low of the external lobe depth. The ventrolateral saddle is strik- among the few specimens. ingly asymmetric and rounded at its top; the adventive lobe The cross section of paratype MB.C.12000 displays is also asymmetric, V-shaped with a convexly curved and the conch ontogeny from the initial to the adult stage steep ventral flank and an oblique, slightly sinuous dorsal (Fig. 21C). Conch growth begins with a serpenticonic flank (Fig. 21A). early juvenile stage, with the relative umbilical width rap- Paratype MB.C.12001.2 represents the preadult stage idly increasing to a maximum of 0.65 at 6 mm conch di- at 30 mm conch diameter (Fig. 20B). It is thinly pachy- ameter. The venter begins to flatten at 2 mm diameter, and conic (ww/dm = 0.61) with a narrow umbilicus (uw/dm = the ventrolateral margin becomes angular. This ‘calyx 0.25). At its largest diameter, the venter changes from stage’ (i.e. the stage with wide umbilicus, sharp umbilical broadly rounded to tectiform and subangular. The conch edge, and flat venter) is visible up to 6 mm diameter, with is thickest at the pronounced umbilical margin that is a flat or slightly concave venter and a sharp ventrolateral slightly elevated to a low rim occupied by fine and sharp edge. Subsequently, the venter becomes convexly nodes. The growth lines run slightly biconvex across rounded, and the former ventrolateral edge becomes an flanks and venter. Constrictions, which are deeper on the angular umbilical margin up to 15 mm diameter. Later internal mould than on the shell surface (Fig. 21B), extend stages show lateral compression of the conch. The largest parallel to the growth lines on the inner flank area, but specimens display tectiform whorl cross sections with form a low ventral projection in contrast to the growth keeled venters. lines. Holotype MB.C.12001.1 is the largest individual with Smaller specimens such as paratype UMNH IP 2690 59 mm conch diameter (Fig. 20A). It represents the dis- (18 mm diameter) are thinly pachyconic (ww/dm = 0.64) cus-shaped ontogenetic stage with an acute venter. The and show a broadly rounded venter as well as an angular

138 Dieter Korn & Alan L. Titus • Goniatites Zone (middle Mississippian) ammonoids, Nevada and Utah

Table 8. Conch ontogeny (Fig. 23) of Calygirtyoceras arcticum (Gordon, 1957). dm conch shape whorl cross section shape aperture 1.5 mm thinly pachyconic; subevolute strongly depressed; moderately embracing (ww/wh ~ 2.00; moderate (WER ~ 1.80) (ww/dm ~ 0.65; uw/dm ~ 0.40) IZR ~ 0.20) 5 mm thickly pachyconic; evolute extremely depressed; moderately embracing (ww/wh = 3.20–3.50; low (WER = 1.55–1.60) (ww/dm = 0.70–0.75; uw/dm = 0.55–0.60) IZR ~ 0.15) 10 mm thickly pachyconic; evolute strongly depressed; moderately embracing (ww/wh = 2.10–2.50; low (WER = 1.60–1.65) (ww/dm = 0.75–0.80; uw/dm = 0.45–0.50) IZR ~ 0.20) 25 mm thickly discoidal; subinvolute weakly depressed; strongly embracing (ww/wh ~ 1.10; moderate (WER ~ 1.80) (ww/dm ~ 0.55; uw/dm ~ 0.25) IZR ~ 0.40) 55 mm thinly discoidal; involute weakly compressed; strongly embracing (ww/wh ~ 0.75; high (WER ~ 2.25) (ww/dm ~ 0.45; uw/dm ~ 0.12) IZR ~ 0.40) umbilical margin (Fig. 20D). The growth lines are tagiak River (Brooks Range); Kuna Formation, most pro- lamellose in this stage and extend with a wide projection bably Calygirtyoceras arcticum Biozone. across the venter, parallel to the irregularly spaced con- strictions. Material. – 111 specimens; conch diameter up to 66 mm. By the end of its ‘calyx stage’ (13 mm diameter) paratype UMNH IP 2689 is thickly pachyconic (ww/dm = Diagnosis. – Species of Calygirtyoceras with a thickly pa- 0.77) with a wide umbilicus (uw/dm = 0.40). Weak ribs or- chyconic, widely umbilicate conch at 6–8 mm diameter nament the sharp umbilical edge. Growth lines and shell (ww/dm = 0.70–0.80; uw/dm = 0.55–0.60), a thickly disco- constrictions run with a wide arch across the broad venter idal, moderately umbilicate conch at 20 mm diameter (Fig. 20E). (ww/dm = 0.50–0.60; uw/dm = 0.25–0.35), and a discoi- dal, narrowly umbilicate conch at 50–60 mm diameter Discussion. – Calygirtyoceras confusionense is the girtyo- (ww/dm = 0.40; uw/dm = 0.10). Whorl cross section shows ceratid with the widest conch among the material from the conspicuous ontogenetic changes; crescent-shaped in early Chainman Formation. Co-occurring specimens of C. arcti- juveniles, later subtrapezoidal with pronounced ventrolate- cum have, at comparable conch diameters, a ww/wh ratio ral margin and flat venter (2–6 mm diameter), followed by 0.10 lower than that of C. confusionense. C. arcticum (Gor- an intermediate stage with rounded venter and angular um- don, 1957) from the Kiruktagiak River in Alaska differs bilical margin (10–20 mm diameter), a preadult stage with from C. confusionense by having a less angular umbilical laterally compressed whorls and a subacute venter margin, a rounded venter in the juvenile stage (applanate or (30–40 mm diameter), and an adult oxyconic stage (50 mm even slightly concave in C. confusionense), and fine spiral diameter). Ornament is fine prorsiradiate growth lines in lines. C. confusionense also exhibits much coarser growth juveniles; later stages with fine and slightly biconvex lines. growth lines, occasionally with fine spiral lines. Weak The Moroccan species C. darkaouaense Korn, Klug shell constrictions in intermediate growth stages. & Mapes, 1999 possesses a wide conch like C. confu- sionense, but lacks the tectiform preadult whorl cross Description. – The ontogeny plots demonstrate the conspi- section and coarse growth lines. Calygirtyoceras cuous developmental changes of the species (Fig. 23). zrigatense Korn & Ebbighausen, 2006, also known from Three distinctive ontogenetic stages can be separated re- Morocco, as well as the European species C. platyforme garding the proportions of the conch dimensions. It is note- (Moore, 1946) and C. moorei (Nicolaus, 1963) have worthy, however, that the three biometric conch parame- more slender conchs. ters whorl width index (ww/dm), umbilical width index (uw/dm) and whorl expansion rate (WER) do not show a parallel development, so that the separation of growth sta- Calygirtyoceras arcticum (Gordon, 1957) ges cannot be sharp. In an early juvenile stage (up to Figures 22, 23 2–3 mm diameter), widening of the umbilicus up to uw/dm = 0.60 is paralleled by a reduction of conch width to *1957 Girtyoceras arcticum Gordon, p. 50, pl. 6, figs 20–22. ww/dm = 0.60 and a reduction of the whorl expansion rate to 1.50. Up to 8 mm diameter, the conch becomes thicker Holotype. – Specimen USNM 118976, illustrated by Gor- and reaches a maximum ww/dm ratio of 0.85. In this don (1957, pl. 6, figs 20–22). growth interval the umbilicus maintains its width and the aperture becomes slightly higher (WER = 1.65). The fol- Type locality and horizon. – USGS locality 14149, Kiruk- lowing growth interval is characterized by a continuous

139 Bulletin of Geosciences • Vol. 86, 1, 2011

B

A C

Figure 22. Calygirtyoceras arcticum (Gordon, 1957).•A–specimen UMNH IP 2725 from bed 7 (sample 93UTMI-25) of Jensen Wash; × 1.0. • B – specimen UMNH IP 2738 from bed 7 (sample 93UTMI-25) of Jensen Wash; × 2.5. • C – specimen UMNH IP 2727 from bed 7 (sample 93UTMI-25) of Jensen Wash; × 2.5.

Table 9. Conch dimensions (in mm) and proportions for reference specimens of Calygirtyoceras arcticum (Gordon, 1957).

dm ww wh uw ah ww/dm ww/wh uw/dm WER IZR UMNH IP 2725 66.0 25.5 36.4 6.9 22.6 0.39 0.70 0.10 2.31 0.38 UMNH IP 2718 31.9 13.0 15.1 7.3 8.9 0.41 0.86 0.23 1.93 0.41 UMNH IP 2724 21.2 12.6 9.8 5.4 5.8 0.60 1.29 0.25 1.89 0.41 UMNH IP 2726 15.7 10.8 6.4 5.6 3.9 0.69 1.69 0.35 1.76 0.39 UMNH IP 2738 15.2 10.0 6.2 5.7 3.8 0.66 1.61 0.38 1.77 0.39 UMNH IP 2727 12.2 8.8 5.1 4.8 2.6 0.73 1.73 0.39 1.60 0.50 decrease in the ww/dm ratio and a simultaneous reduction well-preserved part of the body chamber, when the conch in the relative umbilical width as well as heightening of the has a diameter of 44 mm. The shell has fine, strongly whorl expansion rate. biconvex growth lines in this stage. Two sectioned specimens, UMNH IP 2718 from Gran- The sectioned specimen UMNH IP 2718 (32 mm diam- ite Mountain and UMNH IP 2724 from Jensen Wash, illus- eter) represents the preadult stage; its venter is subacute trate the ontogenetic changes of the conch from the initial and its umbilical margin subangular. The shell is orna- stage up to a diameter of 32 mm (Fig. 23A, B). The inner- mented with fine biconvex growth lines that show a deep most whorls up to 2 mm conch diameter are crescent- ventral sinus. Faint shell constrictions occur on the flanks, shaped, thereafter the venter flattens and development of a particularly in the ventrolateral area (Fig. 23A, D). ventrolateral edge takes place. This ‘calyx stage’ is present Smaller specimens such as UMNH IP 2727 (12 mm di- up to 5.5 mm diameter, followed by a stage in which the ameter) are just past the ‘calyx stage’ (Fig. 23B) and show ventrolateral edge is transformed into a subangular umbili- broadly rounded venters and subangular umbilical mar- cal margin, paralleled by slight lateral compression of the gins. Lamellar growth lines with slightly prorsiradiate whorls that results in a higher aperture. This stage ends at course and faint spiral lines decorate the shell, and the in- about 20 mm diameter, when the venter becomes narrower. ternal mould shows impressions of these growth lines. Ir- By 30 mm diameter the venter is subacute. regularly spaced steinkern constrictions run parallel to the The largest available specimen is UMNH IP 2725 from growth lines. Jensen Wash; it has a conch diameter of 66 mm (Fig. 23A). Suture lines have been obtained from three different The end of the body chamber of the specimen is laterally growth stages (Fig. 23E–G). They show the characteristic crushed, but it can be assumed that it had an oxyconic out- outline of a girtyoceratid species with an ontogenetic wid- line. A subacute venter with inconspicuous ventral nodes ening of the external lobe and a heightening of the median and a rounded umbilical margin can be seen in the saddle.

140 Dieter Korn & Alan L. Titus • Goniatites Zone (middle Mississippian) ammonoids, Nevada and Utah

H

G

I

F

J

E

D

A B C

Figure 23. Calygirtyoceras arcticum (Gordon, 1957).•A–cross section of specimen UMNH IP 2718 from bed 25 (sample 05UTJU-12) of Granite Mountain-South; × 2.5. • B – cross section of specimen UMNH IP 2724 from bed 7 (sample 93UTMI-25) of Jensen Wash; × 2.5.•C–cross section (re- drawn from Gordon, 1957) of paratype USNM 118977 from the Kiruktagiak River; × 2.5.•D–growth line course of specimen UMNH IP 2718 from bed 25 (sample 05UTJU-12) of Granite Mountain-South, at 12.0 mm ww, 12.5 mm wh; × 3.0. • E –suture line of specimen UMNH IP 2727 from bed 7 (sam- ple 93UTMI-25) of Jensen Wash, at 7.2 mm ww, 3.2 mm wh; × 8.0.•F–suture line of specimen UMNH IP 2718 from bed 25 (sample 05UTJU-12) of Granite Mountain-South, at 31.0 mm diameter, 13.0 mm ww, 14.5 mm wh; × 4.0.•G–suture line of specimen UMNH IP 2725 from bed 7 (sample 93UTMI-25) of Jensen Wash, at 18.3 mm ww, 17.5 mm wh; × 3.5. • H–J – ontogenetic development of the conch width index (ww/dm), umbilical width index (uw/dm), whorl width index (ww/wh), and whorl expansion rate (WER) of all available specimens.

Discussion. – Calygirtyoceras confusionense is similar, but tened venter (Fig. 23C). C. arcticum has a wider conch than has a wider conch and umbilicus at comparable diameters. C. platyforme (Moore, 1946), C. moorei (Nicolaus, 1963), The calyx stage is also less well developed in C. arcticum, and C. zrigatense Korn & Ebbighausen, 2006, but is more with a less angular ventrolateral edge and less strongly flat- slender than C. darkaouaense Korn, Klug & Mapes, 1999.

141 Bulletin of Geosciences • Vol. 86, 1, 2011

Figure 24. Ontogenetic trajectories (ww/dm and uw/dm relations) of Girtyoceras from the Chainman Formation of the Antler Foreland Basin and the Caney Shale of Oklahoma; illustrated are growth stages larger than 2 mm diameter. Numbers refer to the conch diameters at which the ratios were taken. Girtyoceras primum sp. nov., paratype UMNH IP 2834; Girtyoceras gordoni sp. nov., paratype UMNH IP 3103; Girtyoceras hamiltonense sp. nov., paratype MB.C.12005.1; Girtyoceras meslerianum (Girty, 1909), specimen MB.C.12040 from Jack Fork Creek near Ada.

Genus Girtyoceras Wedekind, 1918 p. 567; Belgium; cowdalense: Girtyoceras cowdalense Moore, 1946, p. 406; Yorkshire; deani: Girtyoceras deani Type species. – Adelphoceras meslerianum Girty, 1909 Moore, 1946, p. 399; Yorkshire; discus: Goniatites discus (original designation). Roemer 1855, p. 95; Harz [homonym of Goniatites discus Roemer 1850; synonym of G. ibergense]; duekemoerense: Genus definition. – Girtyoceratidae with moderately large Girtyoceras duekemoerense Korn, 1988, p. 54; Rhenish conch (up to 150 mm diameter) that passes through very Mountains; edwinae: Girtyoceras edwinae Korn, 1988, different morphological stages during ontogeny: in early p. 61; Rhenish Mountains; endicottense: Girtyoceras endi- juveniles widely umbilicate (uw/dm = 0.45–0.55) with cottense Gordon, 1957, p. 51; Alaska; excavatum: Goniati- crescent-shaped whorl cross section, later thickly discoidal tes excavatus Phillips, 1836, p. 235; Yorkshire; finale: Gir- or pachyconic with subangular or rounded umbilical mar- tyoceras modestum finale Ruzhencev & Bogoslovskaya, gin, intermediate stage with rounded flanks and venter, and 1971, p. 175; South Urals; glabrum: Girtyoceras glabrum adult stage lenticular-oxyconic. Without or with very faint Ruzhencev & Bogoslovskaya, 1971, p. 171; South Urals; ventrolateral grooves. Suture line with V-shaped external goii: Girtyoceras goii Korn, 1988, p. 58; Rhenish Moun- lobe, moderately high median saddle, narrowly rounded tains; gordoni: Girtyoceras gordoni sp. nov.; Antler Fore- ventrolateral saddle, and V-shaped adventive lobe. land Basin; hamiltonense: Girtyoceras hamiltonense sp. nov.; Antler Foreland Basin; heishantouense: Jeminayce- Included species. – aeulkei: Girtyoceras aeulkei Korn, ras heishantouense Wang, 1983, p. 520; Xinjiang; ibnkhal- 1988, p. 57; Rhenish Mountains; boreale: Girtyoceras bo- douni: Girtyoceras ibnkhaldouni Korn & Ebbighausen, reale Kusina, 1987, p. 58; Novaya Zemlya; brainerdi: Dry- 2008, p. 92; Moroccan Meseta; ibergense: Girtyoceras ochoceras Brainerdi Morgan, 1924, p. 185; Oklahoma [sy- ibergense Korn, 1992, p. 278; Harz; kazakhorum: Girtyo- nonym of G. meslerianum]; brueningianum: Homoceras ceras kazakhorum Ruzhencev, 1966, p. 55; South Urals; brüningianum Schmidt, 1925, p. 580; Rhenish Mountains; latum: Girtyoceras latum Ruzhencev & Bogoslovskaya, complicatum: Ammonites complicatus de Koninck 1844, 1971, p. 170; South Urals; luscinia: Girtyoceras luscinia

142 Dieter Korn & Alan L. Titus • Goniatites Zone (middle Mississippian) ammonoids, Nevada and Utah

A BCDE

G H J F I

Figure 25. Cross sections of the inner whorls of various species of Girtyoceras for comparison; all × 4.•A–Calygirtyoceras confusionense sp. nov., paratype MB.C.12000 from bed 6 of Middle Confusion Range 1.•B–Calygirtyoceras arcticum (Gordon, 1957), specimen UMNH IP 2718 from bed 25 (sample 05UTJU-12) of Granite Mountain-South.•C–Girtyoceras primum sp. nov., paratype UMNH IP 2834 from bed 16 (sample 00UTMI-1n) of Needle Range.•D–Girtyoceras gordoni sp. nov., paratype UMNH IP 3103 from bed 19 (sample 97UTMI-13) of Jensen Wash.•E–Girtyoceras hamiltonense sp. nov., paratype UMNH IP 3128 from bed 44 (sample 07NVWP-3) of Hamilton Canyon.•F–Girtyoceras meslerianum (Girty, 1909), specimen MB.C.12040 from the Delaware Creek Member of the Caney Shale of Jackfork Creek (Oklahoma).•G–Girtyoceras meslerianum (Girty, 1909), specimen USNM 119628 (redrawn from Gordon, 1965) from the Delaware Creek Member of the Caney Shale of USGS locality 2083 (Oklahoma). •H–Girtyoceras luscinia Korn, 1988, specimen MB.C.13213.4 from the Glib en-Nâam Formation of the Chebket el Hamra (Morocco).•I–Girtyoceras ibnkhaldouni Korn & Ebbighausen, 2008, paratype MB.C.13214.4 from the Glib en-Nâam Formation of the Chebket el Hamra (Morocco). •J–Girtyoceras goii Korn, 1988, paratype WMN 10044 (redrawn from Korn, 1988) from the Herdringen Formation of Estinghausen (Rhenish Moun- tains).

Korn, 1988, p. 52; Rhenish Mountains; margaritatum: Gir- Discussion. – Girtyoceras is nearly global in distribution. tyoceras margaritatum Korn, 1988, p. 55; Rhenish Moun- About 30 more or less well-described species are in the li- tains; medium: Girtyoceras modestum medium Ruzhencev terature. Korn & Ebbighausen (2008) gave an overview & Bogoslovskaya, 1971, p. 174; South Urals; meslerianum: on the European species, of which 14 were grouped and Adelphoceras meslerianum Girty, 1909, p. 66; Oklahoma; briefly characterized. These authors separated one group modestum: Girtyoceras modestum modestum Ruzhencev & with thinly discoidal conch (ww/dm = less than 0.50) from Bogoslovskaya, 1971, p. 174; South Urals; premeslerianum: a second group with thickly discoidal or pachyconic conch Girtyoceras premeslerianum Moore, 1946, p. 401; York- (ww/dm = more than 0.50), measured in specimens of shire; primum: Girtyoceras primum sp. nov.; Antler Fore- 15 mm conch diameter. The American species can be grou- land Basin; shorrocksi: Girtyoceras shorrocksi Moore, ped as follows: 1946, p. 413; Lancashire; simplex: Girtyoceras simplex Group A (more slender forms): Moore, 1946, p. 400; Yorkshire; tomasi: Girtyoceras tomasi G. meslerianum (Girty, 1909): slender form (ww/dm = Wagner-Gentis, 1987, p. 31; South Portugal; waitei: Girtyo- 0.42–0.48, uw/dm = 0.22–0.25 at 15 mm diameter) with ceras waitei Moore, 1946, p. 415; Yorkshire; welleri: Girty- strong biconvex constrictions and fine riblets in the juve- oceras welleri Gordon, 1965, p. 233; Arkansas; ?acutum: nile stage; sharpening of the venter at about 20 mm di- Sagittoceras acutum Hind, 1918, p. 447; Yorkshire. ameter;

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Table 10. Conch ontogeny (Fig. 27) of Girtyoceras primum sp. nov. dm conch shape whorl cross section shape aperture 1.5 mm thinly pachyconic; evolute strongly depressed; moderately embracing (ww/wh = 2.15–2.45; low (WER ~ 1.65) (ww/dm = 0.60–0.70; uw/dm = 0.40–0.55) IZR = 0.20–0.25) 5 mm thickly pachyconic; evolute extremely depressed; moderately embracing (ww/wh = 2.70–3.20; low (WER ~ 1.65) (ww/dm = 0.75–0.85; uw/dm = 0.50–0.55) IZR = 0.20–0.25) 10 mm pachyconic; evolute moderately depressed; moderately embracing (ww/wh = 1.70–2.00; moderate (WER ~ 1.80) (ww/dm = 0.70–0.75; uw/dm = 0.40–0.45) IZR = 0.25–0.30) 25 mm thinly discoidal; subinvolute weakly compressed; strongly embracing (ww/wh = 0.80–1.00; high (WER = 2.00–2.25) (ww/dm = 0.40-0.45; uw/dm = 0.15–0.25) IZR = 0.35–0.45) 42 mm extremely discoidal; involute weakly compressed; strongly embracing (ww/wh ~ 0.62; very high (WER ~ 2.26) (ww/dm ~ 0.34; uw/dm ~ 0.12) IZR ~ 0.40)

G. welleri Gordon, 1965: slender form (ww/dm = 0.45, Species of Girtyoceras are usually separated on the basis uw/dm = 0.23 at 14 mm diameter) with weak biconvex of conch shape, ontogeny, and ornament, not sutural charac- constrictions; sharpening of the venter at about 13 mm di- ters. This is mainly because the suture line is often dependent ameter; on the conch form. Species of Girtyoceras can be signifi- G. endicottense Gordon, 1957: slender form (ww/dm = cantly different in their conch shape at comparable diameters, 0.44, uw/dm = 0.26 at 14 mm diameter) with almost and thus suture lines are very difficult to compare. straight constrictions; venter with a fine longitudinal groove, no sharpening of the venter at least until 26 mm di- ameter. Girtyoceras primum sp. nov. Group B (stouter forms): Figures 26, 27 G. primum sp. nov.: stout form (ww/dm = 0.55–0.62, uw/dm = 0.20–0.28 at 15 mm diameter) with weak 1984 Girtyoceras n. sp. A; Webster et al., p. 31. biconvex constrictions, constrictions form a ventral projec- tion in the juvenile stage; sharpening of the venter at about Derivation of name. – After Lat. primum = the first, an allu- 45 mm diameter; sion to its basal phylogenetic position in Girtyoceras. G. gordoni sp. nov.: moderately stout form (ww/dm = 0.50–0.55, uw/dm = 0.20–0.24 at 15 mm diameter) with Holotype. – Specimen UMNH IP 2865, illustrated in strong concavo-convex constrictions with high ventrola- Fig. 26C. teral projection; sharpening of the venter not before 20 mm diameter; Type locality and horizon. – South Burbank Hills, bed 6 G. hamiltonense sp. nov.: slender to moderately stout (sample 01UTMI-3); Camp Canyon Member of Chainman form (ww/dm = 0.48–0.53, uw/dm = 0.15–0.25 at 15 mm Formation, Girtyoceras primum Biozone. diameter) with strong biconvex constrictions with moder- ately high ventrolateral projection; sharpening of the Material. – The holotype and 320 paratypes; conch diame- venter at about 40 mm diameter. ter up to 77 mm. The three Chainman Formation species are all stouter forms, in contrast to the Alaskan and American Diagnosis. – Species of Girtyoceras with a thickly pachyco- Midcontinent forms. Within the succession in the Chain- nic, widely umbilicate conch at 6–8 mm diameter (ww/dm = man Formation, a trend from stouter towards more slender 0.80–0.90; uw/dm = 0.45–0.55), a thickly discoidal, nar- forms can be observed (Fig. 24). rowly umbilicate conch at 20 mm diameter (ww/dm = Another trend within the genus is the regression of the 0.45–0.55; uw/dm = 0.25–0.35), and a discoidal, narrowly angular umbilical margin in the juvenile stage towards a umbilicate conch at 40 mm diameter (ww/dm = 0.35–0.40; rounded umbilical margin. This trend has already begun in uw/dm = 0.10–0.15). Whorl cross section extremely depres- the genus Calygirtyoceras, but the angular umbilical mar- sed in the juveniles (2–8 mm diameter), followed by an in- gin is still present in stratigraphically older species of termediate stage with rounded venter and subangular umbi- Girtyoceras, such as G. primum (Fig. 25). The youngest lical margin (10–20 mm diameter), a preadult stage with species from the Camp Canyon Member is G. hamilto- laterally compressed whorls and rounded venter (30–40 mm nense, which has an almost rounded umbilical margin, sim- diameter), and an adult oxyconic stage (50 mm diameter). ilar to G. meslerianum from the Caney Shale and to the Eu- Ornament of fine prorsiradiate growth lines in juveniles; la- ropean/African species G. luscinia, G. ibnkhaldouni, and ter stages show fine biconvex growth lines. Very weak shell G. goii, of which the inner whorls are well-known. constrictions in intermediate growth stages.

144 Dieter Korn & Alan L. Titus • Goniatites Zone (middle Mississippian) ammonoids, Nevada and Utah

B

A

C

D EF

Figure 26. Girtyoceras primum sp.nov.•A–paratype UMNH IP 2835 from bed 16 (sample 00UTMI-1n) of Needle Range; × 1.0.•B–paratype UMNH IP 2952 from bed 25 (sample 05UTJU-12) of Granite Mountain South; × 1.5.•C–holotype UMNH IP 2865 from bed 6 (sample 01UTMI-3) of South Burbank Hills; × 1.5.•D–paratype UMNH IP 2864 from bed 6 (sample 01UTMI-3) of South Burbank Hills; × 2.0.•E–paratype UMNH IP 3084 from bed 25 (sample 94UTJU-9) of Granite Mountain South; × 2.0. • F – paratype UMNH IP 2953 from bed 25 (sample 05UTJU-12) of Granite Mountain South; × 2.0.

Description. – Four paratypes were sectioned to study the Paratype UMNH IP 2834 is a cross section that displays conch ontogeny (of which three are illustrated in the ontogeny up to 32 mm conch diameter (Fig. 27A). Its Fig. 27A–C), and a number of specimens were measured. conch ontogeny begins with crescent-shaped early whorls, Therefore, the ontogeny plots allow an insight in the intras- and up to 6 mm diameter, the whorl cross section is pecific variability of the species (Fig. 27K–M). Juveniles strongly depressed ventrally with a wide and broadly up to 7 mm conch diameter show an especially wide range rounded venter. At 8 mm diameter, the whorl becomes of conch thickness, whereas growth stages above 8 mm higher, resulting in an increase of the whorl expansion rate diameter are almost uniform. Variability in the uw/dm in- (WER = 1.75). This trend is retained in the following dex as well as the whorl expansion rate is limited. The plots whorls, where the WER is continuously raised to a value of show the characteristic ontogenetic patterns of a girtyoce- 2.22 at 32 mm diameter. The conch is lenticular in this ratid species; (1) a serpenticonic stage up to 3 mm diame- stage, with a ww/dm ratio of 0.44, compressed whorl, and a ter, (2) a cadyconic stage between 3 and 10 mm diameter, narrowly rounded venter. and a laterally compressed preadult and adult stage with Paratype UMNH IP 2835 is, with a maximum diameter extreme narrowing of the umbilicus. of 77 mm, the largest available specimen (Fig. 26A). Its

145 Bulletin of Geosciences • Vol. 86, 1, 2011

K

J L

I

H M

B G

F

E

A C D

Figure 27. Girtyoceras primum sp.nov.•A–cross section of paratype UMNH IP 2834 from bed 16 (sample 00UTMI-1n) of Needle Range; × 2.5. • B – cross section of paratype UMNH IP 2836 from bed 16 (sample 00UTMI-1n) of Needle Range; × 2.5.•C–cross section of paratype UMNH IP 2837 from bed 16 (sample 00UTMI-1n) of Needle Range; × 2.5.•D–constriction course of paratype UMNH IP 2953 from bed 25 (sample 05UTJU-12) of Granite Mountain South, at 8.0 mm ww, 4.7 mm wh; × 4.0.•E–growth line and constriction course of paratype UMNH IP 2951 from bed 25 (sample 05UTJU-12) of Granite Mountain South, at 11.2 mm ww, 8.8 mm wh; × 4.0. • F – constriction course of paratype UMNH IP 2952 from bed 25 (sample 05UTJU-12) of Granite Mountain South, at 10.4 mm ww, 10.3 mm wh; × 4.0. • G, constriction course of paratype UMNH IP 2952 from bed 25 (sample 05UTJU-12) of Granite Mountain South, at 24.9 mm diameter, 12.3 mm ww, 14.0 mm wh; × 4.0.•H–suture line of paratype UMNH IP 2953 from bed 25 (sample 05UTJU-12) of Granite Mountain South, at 8.0 mm ww, 4.7 mm wh; × 5.0.•I–suture line of paratype UMNH IP 2952 from bed 25 (sample 05UTJU-12) of Granite Mountain South, at 10.4 mm ww, 10.3 mm wh; × 5.0.•J–suture line of paratype UMNH IP 2952 from bed 25 (sample 05UTJU-12) of Granite Mountain South, at 26.5 mm diameter, 12.5 mm ww, 14.3 mm wh; × 5.0. • K–M – ontogenetic development of the conch width index (ww/dm), umbilical width index (uw/dm), whorl width index (ww/wh), and whorl expansion rate (WER) of all available specimens. discus-shaped body chamber is crushed but it is clear that the Holotype UMNH IP 2865 is a fully septate conch with conch is oxyconic with a sharp venter by 40 mm diameter. 42 mm diameter and shows the transformation into the Only some shell remains are preserved at this diameter; they adult oxyconic stage; the venter becomes sharpe at 30 mm show fine biconvex growth lines. There are no constrictions. diameter (Fig. 26C). The lenticular conch (ww/dm = 0.34)

146 Dieter Korn & Alan L. Titus • Goniatites Zone (middle Mississippian) ammonoids, Nevada and Utah

Table 11. Conch dimensions (in mm) and proportions for reference specimens of Girtyoceras primum sp. nov.

dm ww wh uw ah ww/dm ww/wh uw/dm WER IZR HT UMNH IP 2865 42.1 14.3 23.1 5.2 14.1 0.34 0.62 0.12 2.26 0.39 PT UMNH IP 2834 32.1 14.3 18.8 2.3 10.5 0.44 0.76 0.07 2.22 0.44 PT UMNH IP 2952 29.3 12.9 15.2 5.8 9.4 0.44 0.85 0.20 2.17 0.38 PT UMNH IP 2864 25.0 9.9 13.2 4.1 8.3 0.40 0.75 0.16 2.23 0.37 PT UMNH IP 3084 17.7 9.9 8.6 3.8 5.1 0.56 1.15 0.22 1.97 0.41 PT UMNH IP 2836 16.0 8.8 6.4 5.6 4.2 0.55 1.37 0.35 1.85 0.34 PT UMNH IP 2953 15.1 8.9 7.2 3.4 4.0 0.59 1.24 0.22 1.85 0.44 PT UMNH IP 2837 13.9 8.6 5.7 4.5 3.7 0.62 1.51 0.33 1.86 0.35 has a narrow umbilicus (uw/dm = 0.12) with a narrowly ras, as indicated by the presence of prorsiradiate, ventrally rounded umbilical margin. Shell remains show biconvex projecting constrictions in juveniles. growth lines; neither shell surface nor the internal mould The constrictions of G. primum show only moderately possesses constrictions. high ventrolateral projection, and this can be used to readily Constrictions of the internal mould are preserved in separate it from the stratigraphically younger species G. smaller specimens such as paratype UMNH IP 2954. This gordoni, G. hamiltonense, and G. meslerianum (Girty, specimen from Granite Mountain has a diameter of 36 mm 1909) from North America. G. endicottense Gordon, 1957 is and closely resembles the holotype in conch parameters a similar species, but differs in the more slender conch at and shell ornament. comparable diameters and in presence of a ventral groove. The well-preserved paratype UMNH IP 2952 is fully Species of similar stratigraphic age from Europe are septate and almost 30 mm in diameter (Fig. 26B). It shows G. excavatum, G. simplex, G. premeslerianum, and steinkern constrictions 90° apart. The first of these is barely G. ibergense; they differ from G. primum mainly in the more visible; the other three show a change in their course from slender conch, the slightly narrower umbilicus, and the prorsiradiate with a ventral projection to a biconvex course biconvex constrictions in the intermediate growth stage. with a ventral sinus (Fig. 27F, G). Conch ratios of the spec- The stratigraphically younger European species G. brue- imen are ww/dm = 0.44, uw/dm = 0.20. ningianum (Schmidt, 1925), G. goii Korn, 1988, and Paratype UMNH IP 3084 has a diameter of 18 mm and G. margaritatum Korn, 1988 have a similar conch shape, but is partly covered with shell (Fig. 26E). The growth lines are show, in the juvenile stage, a ventral sinus of the constric- fine and extend almost linearly across flanks and venter. tions, in contrast to the ventral projection in G. primum. Some weak spiral lines can be seen on the venter. Rather deep, irregularly arranged steinkern constrictions are slightly prorsiradiate with a shallow ventral projection; Girtyoceras gordoni sp. nov. they are much weaker on the shell surface. Figures 28, 29 Two suture lines were drawn from paratype UMNH IP 2952 (Fig. 27I, J). At 26.5 mm diameter, there is a Derivation of name. – Named after Mackenzie Gordon Jr., wide external lobe with slightly sinuous flanks and a me- to honour his contributions to Carboniferous ammonoid dian saddle that reaches almost half the height of the ex- palaeontology. ternal lobe depth. The ventrolateral saddle is slightly asymmetric and rounded, on the flank followed by an Holotype. – Specimen UMNH IP 3093, illustrated in asymmetric adventive lobe that is much smaller than the Fig. 28A. external lobe. Type locality and horizon. – South Burbank Hills, bed 16; Discussion. – Girtyoceras primum differs from other girty- Camp Canyon Member of Chainman Formation, Girtyoce- oceratids in the Chainman Formation in the following: the ras gordoni Biozone. two Calygirtyoceras species have a much wider conch (ww/dm = 0.60 at 20 mm dm in contrast to 0.45 in G. pri- Material. – The holotype and 26 paratypes; conch diameter mum) and a distinct calyx stage with an angular ventrolate- up to 21 mm. ral edge. G. primum may sometimes show tendencies to also show such juvenile stage, but always has a much more Diagnosis. – Species of Girtyoceras with a pachyconic, wi- rounded ventrolateral edge. However, it is obvious G. pri- dely umbilicate conch at 6–8 mm diameter (ww/dm = mum holds a phylogenetic position close to Calygirtyoce- 0.70–0.80; uw/dm = 0.55–0.60), and a thickly discoidal,

147 Bulletin of Geosciences • Vol. 86, 1, 2011

A B

CD

Figure 28. Girtyoceras gordoni sp.nov.•A–holotype UMNH IP 3093 from bed 16 (sample 01UTMI-4) of South Burbank Hills; × 3.0. • B – paratype UMNH IP 3102 from bed, 19 (sample 97UTMI-13) of Jensen Wash; × 3.0. • C – paratype UMNH IP 3094 from bed 16 (sample 01UTMI-4) of South Burbank Hills; × 3.0. • D – paratype UMNH IP 3095 from bed 16 (sample 01UTMI-4) of South Burbank Hills; × 3.0. narrowly umbilicate conch at 20 mm diameter (ww/dm = lunate. In later stages, the whorls become laterally com- 0.45–0.50; uw/dm = 0.15–0.20). Whorl cross section extre- pressed with a higher aperture, resulting in a higher whorl mely depressed in juveniles (2–6 mm diameter), followed expansion rate that exceeds the value of 2.00 at 18 mm by an intermediate stage with rounded venter and angular conch diameter. umbilical margin (above 7 mm diameter), and a discoidal None of the specimens shows an oxyconic adult stage. stage (20 mm diameter) with narrowly rounded venter. Or- Holotype UMNH IP 3093, at 20 mm conch diameter, is the nament with coarse prorsiradiate growth lines in all stages largest of the well-preserved specimens (Fig. 28A); it is up to 20 mm conch diameter, their course is concavo- discoidal (ww/dm = 0.45) with a narrow umbilicus convex in juveniles and biconvex in later stages. Strong (uw/dm = 0.16) and has a narrowly rounded venter with a shell constrictions in intermediate growth stages. barely visible keel. It can be assumed therefore that this specimen is close to the beginning of the adult conch. The Description. – The two sectioned paratypes UMNH IP last quarter of the last volution is a part of the body cham- 3103 and UMNH IP 3096 (Fig. 29A, B) are similar but dif- ber; its internal mould displays an undulation with delicate fer in details such as the width of the whorls (UMNH IP biconvex traces of strengthened growth lines. The cham- 3103 has wider whorls), the height of the aperture (higher bered portion shows three continuously weakening con- in UMNH IP 3096), and the umbilical margin (more angu- strictions, which are best seen on the internal mould. The lar in UMNH IP 3103). Both specimens display the typical coarse growth lines extend with biconvex course across significant ontogenetic changes, with a serpenticonic ini- flanks and venter, forming a low dorsolateral projection, a tial stage up to 1.5–2 mm diameter, followed by a stage in prominent ventrolateral projection, and a shallow ventral which the whorl width increases rapidly to form a broad- sinus. trapezoidal whorl cross section. Opening of the umbilicus Paratype UMNH IP 3095 is characteristic for the inter- occurs up to 8 mm conch diameter, thereafter it maintains mediate growth stage (Fig. 28B). It has a diameter of its absolute width (Fig. 29E–G). The umbilical margin is 13.5 mm and is thickly discoidal (ww/dm = 0.53) with a subangular in this stage and the whorl cross section is semi- narrow umbilicus (uw/dm = 0.26). The flanks and venter

148 Dieter Korn & Alan L. Titus • Goniatites Zone (middle Mississippian) ammonoids, Nevada and Utah

Figure 29. Girtyoceras gordoni sp. E nov.•A–cross section of paratype UMNH IP 3103 from bed 19 (sample 97UTMI-13) of Jensen Wash; × 2.5. • B – cross section of paratype UMNH IP 3096 from bed 16 (sample 01UTMI-4) of South Burbank Hills; ×2.5.•C–constriction course of D paratype UMNH IP 3095 from bed 16 (sample 01UTMI-4) of South Burbank Hills, at 12.4 mm diameter, 6.9 mm ww, F 5.3mmwh;×5.0.•D–suture line of paratype UMNH IP 3101 from bed, 19 (sample 97UTMI-13) of Jensen Wash, at 8.1 mm ww, 6.9 mm wh; × 5.0. • E–G – ontogenetic development of the C conch width index (ww/dm), umbilical width index (uw/dm), whorl width index (ww/wh), and whorl expansion rate (WER) of all available specimens. G

A B

Table 12. Conch ontogeny (Fig. 29) of Girtyoceras gordoni sp. nov. dm conch shape whorl cross section shape aperture 1.5 mm thinly pachyconic; evolute strongly depressed; moderately embracing (ww/wh = 2.15–2.25; low (WER ~ 1.55) (ww/dm = 0.60–0.65; uw/dm = 0.50–0.55) IZR = 0.20–0.25) 5 mm thickly pachyconic; evolute extremely depressed; moderately embracing (ww/wh = 2.70–3.20; low (WER ~ 1.55) (ww/dm = 0.70–0.80; uw/dm = 0.50–0.55) IZR = 0.20–0.25) 10 mm thinly pachyconic; subevolute moderately depressed; strongly embracing (ww/wh = 1.50–1.90; low (WER ~ 1.70) (ww/dm = 0.60–0.65; uw/dm = 0.35–0.40) IZR ~ 0.40) 20 mm thinly discoidal; subinvolute weakly compressed; strongly embracing (ww/wh ~ 0.95; high (WER ~ 2.10) (ww/dm ~ 0.45; uw/dm ~ 0.16) IZR ~ 0.40)

Table 13. Conch dimensions (in mm) and proportions for reference specimens of Girtyoceras gordoni sp. nov.

dm ww wh uw ah ww/dm ww/wh uw/dm WER IZR HT UMNH IP 3093 20.5 9.1 9.6 3.3 6.4 0.45 0.95 0.16 2.11 0.34 PT UMNH IP 3103 17.9 9.5 8.6 3.9 5.0 0.53 1.09 0.22 1.92 0.42 PT UMNH IP 3096 17.9 8.2 9.1 3.5 5.3 0.46 0.90 0.19 2.04 0.41 PT UMNH IP 3101 17.1 9.1 11.8 2.5 – 0.53 0.77 0.15 – – PT UMNH IP 3102 14.5 8.3 6.9 3.5 4.1 0.57 1.20 0.24 1.95 0.41 PT UMNH IP 3095 13.5 7.2 5.8 3.6 3.6 0.53 1.24 0.26 1.85 0.38 PT UMNH IP 3094 10.7 5.8 4.7 3.1 2.7 0.55 1.24 0.29 1.80 0.42 are broadly rounded, and the umbilical margin is angular. The inner whorls of paratype UMNH IP 3104 are trape- The specimen shows deep constrictions on the internal zoidal in cross section and possess a sharp umbilical wall mould, which form prominent ventrolateral projections ornamented by faint nodes. At this stage, the umbilicus is and shallow ventral sinuses (Fig. 29C). wide and the venter is flattened.

149 Bulletin of Geosciences • Vol. 86, 1, 2011

Table 14. Conch ontogeny (Fig. 31) of Girtyoceras hamiltonense sp. nov.

dm conch shape whorl cross section shape aperture thickly discoidal; evolute moderately depressed; moderately embracing 1.5 mm low (WER ~ 1.60) (ww/dm = 0.50–0.60; uw/dm = 0.45–0.50) (ww/wh = 1.80–2.00; IZR = 0.20–0.25) thinly pachyconic; evolute strongly depressed; moderately embracing 5 mm low (WER = 1.55–1.65) (ww/dm = 0.60–0.70; uw/dm = 0.45–0.55) (ww/wh = 2.10–2.50; IZR = 0.25–0.30) thickly discoidal; subevolute weakly depressed; strongly embracing 10 mm moderate (WER = 1.65–1.75) (ww/dm = 0.55–0.60; uw/dm = 0.30–0.35) (ww/wh = 1.25–1.50; IZR = 0.35–0.40) thinly discoidal; involute weakly compressed; strongly embracing (ww/wh = 0.70; 25 mm high (WER ~ 2.05) (ww/dm ~ 0.38; uw/dm ~ 0.12) IZR ~ 0.40) extremely discoidal; involute strongly compressed; strongly embracing (ww/wh ~ 0.45; 55 mm very high (WER ~ 2.45) (ww/dm ~ 0.25; uw/dm ~ 0.05) IZR ~ 0.40)

The suture line of paratype UMNH IP 3101 has the typ- Material. – The holotype and 106 paratypes; conch diame- ical outline of the genus (Fig. 29D). The V-shaped external ter up to 54 mm. lobe has slightly curved flanks and a median saddle of al- most half the height of the external lobe. The adventive Diagnosis. – Species of Girtyoceras with a pachyconic, wi- lobe is much smaller and V-shaped. dely umbilicate conch at 6–8 mm diameter (ww/dm = 0.62–0.72; uw/dm = 0.45–0.55), and a thickly discoidal, Discussion. – Girtyoceras gordoni is very similar to G. ha- very narrowly umbilicate conch at 20 mm diameter miltonense, but juveniles of the former have a more angular (ww/dm = 0.40–0.45; uw/dm = 0.10–0.15). Whorl cross umbilical edge and growth lines and constrictions in the section strongly depressed in juveniles (2–6 mm diameter), thickly discoidal, strongly sulcated ‘sulcatum stage’ (bi- followed by an intermediate stage with rounded venter and convex in G. gordoni, concavo-convex in G. hamilto- angular umbilical margin (above 7 mm diameter), and a nense). Also, constrictions of G. hamiltonense persist until discoidal stage (20 mm diameter) with narrowly rounded the venter is acute, whereas in G. gordoni, they disappear venter. Ornament with coarse prorsiradiate growth lines in earlier, when the venter is rounded. all stages, their course is concavo-convex in juveniles and The new species has a stouter conch (ww/dm = 0.45 the intermediate stage and biconvex in later stages. Strong at 20 mm diameter) than G. meslerianum (ww/dm = shell constrictions in intermediate growth stages. 0.40) and a less angular umbilical margin. The growth lines are stronger in G. gordoni, a criterion that distin- Description. – Cross sections made from the type suite are guishes the species also from other advanced species of all similar allowing for accurate characterization of the on- the genus. togenetic trajectories of the species (Fig. 31A–D). Five sta- ges of conch ontogeny can be separated, (1) a serpenticonic initial stage, (2) the ‘calyx stage’ with pronounced umbili- Girtyoceras hamiltonense sp. nov. cal edge that separates the oblique umbilical wall from the Figures 30, 31 almost flat venter, (3) the ‘sulcatum stage’, in which the whorl cross section is crescent-shaped, (4) the ‘excavatum 1949 Girtyoceras aff. G. meslerianum (Girty 1911); Miller stage’ (the stage with strongly curved constrictions) with et al., p. 608, pl. 99, figs 9, 10. lateral flattening of the conch and stagnation of umbilical 1970 Girtyoceras meslerianum (Girty); Gordon, p. 821. opening, and (5) the ‘discus stage’, in which the conch be- 1984 Girtyoceras meslerianum (Girty); Webster et al., comes lenticular with an acute venter. These transforma- p. 31. tions cause significant changes in the ww/dm, uw/dm, and WER plots, as illustrated in Fig. 31G–I. Derivation of name. – Named for Hamilton Canyon, Ne- Paratype UMNH IP 3188 is a fully mature vada, source of the type specimens. phragmocone with a diameter of 54 mm (Fig. 30A). The conch is disc-shaped (ww/dm = 0.27) with a very narrow Holotype. – Specimen UMNH IP 3127, illustrated in umbilicus (uw/dm = 0.06). The venter is subacute in the Fig. 30B. first quarter of the last whorl and acute thereafter. The specimen has a high aperture with a whorl expansion rate Type locality and horizon. – Hamilton Canyon, bed 44; of 2.48. Attached shell remains are almost smooth except Camp Canyon Member of Chainman Formation, Goniati- for delicate growth lines that form a prominent tes eganensis Biozone. ventrolateral projection. Faint nodes are preserved on the

150 Dieter Korn & Alan L. Titus • Goniatites Zone (middle Mississippian) ammonoids, Nevada and Utah

Figure 30. Girtyoceras hamiltonen- se sp.nov.•A–paratype UMNH IP 3188 from bed 44 (sample 95NVWP-16) of Hamilton Canyon; ×1.0.•B–holotype UMNH IP 3127 from bed 44 (sample 07NVWP-3) of Hamilton Canyon; × 1.5. • C – para- type MB.C.12005.1 from bed 44 of Hamilton Canyon; × 3.0.•D–para- type UMNH IP 3120 from bed 25 (sample 01UTMI-5) of South Burbank Hills; × 3.0.

A B

C D acute venter. The internal mould is smooth except for im- flanks; they turn forward to form a prominent ventrolateral pressions of rhythmically strengthened growth lines. projection and a shallow external sinus. The transition from the preadult to the adult stage is Suture lines show the course that is characteristic for a best seen in the holotype UMNH IP 3127 (Fig. 30B). It has Girtyoceras species. The adult paratype UMNH IP 3188 33 mm diameter and is lenticular (ww/dm = 0.34) with a has, at 36 mm diameter, a wide external lobe with strongly very narrow umbilicus (uw/dm = 0.08) and a high aperture diverging flanks, an asymmetric ventrolateral saddle, and (WER = 2.42). The last whorl of the entirely septate speci- an asymmetric adventive lobe with a strongly curved dor- men begins with a rounded venter, which transforms into sal flank (Fig. 31F). an acute shape by the end of the whorl. One biconvex con- striction is visible on the internal mould; they completely Discussion. – For a comparison with the similar species disappear as the venter becomes sharply angular. G. gordoni, see above under that species. Girtyoceras mes- Paratype MB.C.12005.1 (15 mm diameter) represents lerianum is also similar, but has a more compressed conch an intermediate growth stage, where the discoidal conch and wider umbilicus (uw/dm = 0.30 at 15 mm dm). The (ww/dm = 0.49) begins to flatten and the umbilicus begins course of the constrictions, which are, in the intermediate to close (uw/dm = 0.23). The specimen shows a coarse stage, strongly bent forward in the new species, is the main shell ornament with concavo-convex growth lines and difference from European species such as G. ibergense, deep radial constrictions following the growth lines in their G. brueningianum, G. goii, G. deani, and G. excavatum. course (Fig. 30C). A ventrolateral projection begins to de- velop at about 14 mm diameter. The constrictions are stronger on the internal mould, where the growth lines are Superfamily Dimorphocerataceae Hyatt, 1884 also impressed (Fig. 31E). Family Dimorphoceratidae Hyatt, 1884 Smaller specimens like paratype UMNH IP 3120 (13 mm diameter) are thickly discoidal (ww/dm = 0.53) Family definition. – Dimorphocerataceae with a high, and possess a moderately wide umbilicus (uw/dm = 0.29). parallel-sided median saddle. This specimen is an internal mould, on which there are five pronounced concavo-convex constrictions and impressed Included subfamilies. – Dimorphoceratinae Hyatt, 1884; growth lines (Fig. 30D). Constrictions are concave on the Glyphiolobinae Ruzhencev & Bogoslovskaya, 1969.

151 Bulletin of Geosciences • Vol. 86, 1, 2011

G

F

H

E

I

A BC D

Figure 31. Girtyoceras hamiltonense sp.nov.•A–cross section of paratype MB.C.12005.2 from bed 44 of Hamilton Canyon; × 2.5.•B–cross section of paratype MB.C.12005.3 from bed 44 of Hamilton Canyon; × 2.5.•C–cross section of paratype UMNH IP 3128 from bed 44 (sample 07NVWP-3) of Hamilton Canyon; × 2.5.•D–cross section of paratype UMNH IP 3150 from bed 25 (sample 07UTMI-1) of South Burbank Hills; × 2.5.•E–constriction course of paratype MB.C.12005.1 from bed 44 of Hamilton Canyon, at 14.5 mm diameter, 7.0 mm ww, 6.7 mm wh; × 4.0. • F – suture line of paratype UMNH IP 3188 from bed 44 (sample 99NVWP-15) of Hamilton Canyon, at 35.7 mm diameter, 11.0 mm ww, 21.2 mm wh; × 3.0. • G–I – ontogenetic de- velopment of the conch width index (ww/dm), umbilical width index (uw/dm), whorl width index (ww/wh), and whorl expansion rate (WER) of all avail- able specimens.

Table 15. Conch dimensions (in mm) and proportions for reference specimens of Girtyoceras hamiltonense sp. nov.

dm ww wh uw ah ww/dm ww/wh uw/dm WER IZR PT UMNH IP 3188 53.9 14.8 31.1 3.4 19.7 0.27 0.47 0.06 2.48 0.37 HT UMNH IP 3127 33.2 11.1 18.7 2.8 11.9 0.34 0.60 0.08 2.42 0.37 PT MB.C.12005.3 15.2 7.3 7.5 2.9 4.5 0.48 0.98 0.19 2.00 0.41 PT MB.C.12005.1 15.2 7.4 7.1 3.4 4.3 0.49 1.05 0.23 1.93 0.40 PT UMNH IP 3128 15.0 7.9 6.2 4.0 3.7 0.53 1.26 0.27 1.75 0.41 PT UMNH IP 3150 14.5 7.4 6.2 4.0 3.4 0.51 1.19 0.28 1.72 0.45 PT MB.C.12005.2 13.3 6.8 6.2 3.2 3.7 0.51 1.09 0.24 1.91 0.41 PT UMNH IP 3120 13.1 6.9 5.5 3.8 3.7 0.53 1.25 0.29 1.93 0.33

Subfamily Dimorphoceratinae Hyatt, 1884 Genus Dimorphoceras Hyatt, 1884

Subfamily definition. – Dimorphoceratidae with an unsub- Type species. – Goniatites Gilbertsoni Phillips, 1836 (sub- divided adventive lobe. sequent designation by Foord & Crick 1897).

Included genera. – Dimorphoceras Hyatt, 1884; Trizono- Genus definition. – Dimorphoceratinae with an external ceras Girty, 1909; Asturoceras Ruzhencev & Bogoslov- lobe, in which both secondary prongs are subdivided into skaya, 1969. two large tertiary lobes.

152 Dieter Korn & Alan L. Titus • Goniatites Zone (middle Mississippian) ammonoids, Nevada and Utah

Included species. – algens: Dimorphoceras algens Gor- don, 1957, p. 55; Alaska; brancoi: Dimorphoceras Brancoi Holzapfel, 1889, p. 38; Rhenish Mountains; dnieperense: Dimorphoceras dnieperense Kusina, 1991, p. 41; Donets Basin; gilbertsoni: Goniatites Gilbertsoni Phillips, 1836, p. 236; Lancashire; holzapfeli: Dimorphoceras Holzapfeli Haug, 1898, p. 109; Rhenish Mountains [synonym of D. brancoi]; kathleenae: Dimorphoceras kathleeni Moore, 1936, p. 190; Lancashire; leagramense: Dimorphoceras le- agramense Riley, 1996, p. 22; Lancashire; rileyi: Dimor- phoceras rileyi sp. nov.; Antler Foreland Basin; worki: Di- morphoceras worki sp. nov.; Antler Foreland Basin.

Dimorphoceras worki sp. nov. Figures 32, 33C

Derivation of name. – After David Work, to honour his Figure 32. Dimorphoceras worki sp. nov. Holotype UMNH IP 3229 contributions to Carboniferous ammonoid palaeontology. from bed 4 (sample 01UTMI-2) of South Burbank Hills; × 2.

Holotype. – Specimen UMNH IP 3229, illustrated in Fig. 32.

Type locality and horizon. – South Burbank Hills, bed 4; Camp Canyon Member of Chainman Formation, Calygir- tyoceras arcticum Biozone. C Material. – Only the holotype; conch diameter 36 mm but fully septate.

Diagnosis. – Species of Dimorphoceras with a discoidal conch (ww/dm = 0.45) and narrowly rounded venter. Shell is almost smooth, with very fine biconvex growth lines. Su- B ture line with very high median saddle, acute secondary prongs of the external lobe, rounded ventrolateral saddle, and asymmetric and acute adventive lobe with a convex ventral and a concave dorsal flank. A Description. – The single specimen has a diameter of 36 mm and is fully chambered. It is discoidal (ww/dm = Figure 33. Species of Dimorphoceras.•A–Dimorphoceras rileyi sp. 0.43) with a closed umbilicus and broadly rounded venter nov, suture line of paratype UMNH IP 3248 from bed 17 (sample (Fig. 32). The conch is thickest near the funnel-shaped um- 94UTJU-1) of Granite Mountain South, at 10.2 mm diameter, 5.1 mm bilicus, from which the slightly flattened flanks converge ww,5.8mmwh;×8.•B–Dimorphoceras rileyi sp. nov, suture line of holotype UMNH IP 3253 from bed 17 (sample 07UTJU-1) of Granite to the venter. The aperture is high, causing a whorl expan- Mountain North, at 12.5 mm diameter, 6.5 mm ww, 7.5 mm wh; × 6. sion rate of 2.84. •C–Dimorphoceras worki sp. nov, suture line of holotype UMNH IP Poorly preserved smooth shell remains are attached to 3229 from bed 4 (sample 01UTMI-2) of South Burbank Hills, at 34.0 mm the specimen. The suture line has the characteristic appear- diameter, 14.8 mm ww, 19.2 mm wh; × 2.5. ance for Dimorphoceras, with the bifid prongs of the exter- nal lobe (Fig. 33C). Secondary subdivision of the external with a well-rounded top. On the middle of the flank lies the lobe resulted in two almost similar-sized secondary asymmetric cuneiform adventive lobe with a convex ven- prongs, of which the dorsal one (E1) is slightly deeper and tral and a concave dorsal side. wider than the ventral one (E2). Both secondary lobes are lanceolate and pointed; they are separated by a spatulate Discussion. – Dimorphoceras worki is, with an estimated subsidiary saddle. The ventrolateral saddle is asymmetric maximum conch diameter of approximately 50 mm, a very

153 Bulletin of Geosciences • Vol. 86, 1, 2011

Table 16. Conch dimensions (in mm) and proportions for the holotype of Dimorphoceras worki sp. nov.

dm ww wh uw ah ww/dm ww/wh uw/dm WER IZR HT UMNH IP 3229 36.3 15.6 22.0 0.0 14.8 0.43 0.71 0.00 2.84 0.33

A B

Figure 34. Dimorphoceras rileyi sp.nov.•A–holotype UMNH IP 3253 from bed 17 (sample 07UTJU-1) of Granite Mountain North; × 4. • B – paratype UMNH IP 3246 from bed 17 (sample sample 94UTJU-1) of Granite Mountain South; × 4. large representative when compared with other species of Shell is almost smooth, with very fine biconvex growth li- the entire family Dimorphoceratidae. D. kathleenae (preli- nes and faint spiral lines. Suture line with high median sad- minarily named D. kathleeni in Moore 1931) is similar but dle, acute secondary prongs of the external lobe, rounded has a slightly narrower conch and a suture line in which the ventrolateral saddle, and tongue-shaped, blunt adventive strongly asymmetric E2 lobe is wider than the E1 lobe (the lobe. species may belong in the genus Trizonoceras). D. gilbert- soni has a very low saddle that separates the E1 and E2 lo- Description. – The best-preserved specimen is holotype bes and is thus clearly separated from D. worki. D. rileyi UMNH IP 3253 with a conch diameter of 15.7 mm from the Chainman Formation has a blunt adventive lobe (Fig. 34A). It is entirely septate with twenty chambers and which readily distinguishes it. possesses patches of the shell. The conch is thickly lenticu- lar (ww/dm = 0.51) with an almost closed umbilicus and a high aperture (WER = 2.50). The conch is widest near the Dimorphoceras rileyi sp. nov. funnel-shaped umbilicus, which shows a flattened oblique Figures 33A, B, 34 wall. The shell remains show very fine growth lines with a pronounced ventrolateral saddle and faint, irregularly ar- Derivation of name. – After Nicholas J. Riley, to honour ranged spiral lines. his contributions to Carboniferous palaeontology and stra- Smaller specimens such as paratype UMNH IP 3246 tigraphy. (10.2 mm diameter) are very similar in the conch propor- tions (ww/dm = 0.52; WER = 2.52). The umbilical wall is Holotype. – Specimen UMNH IP 3253, illustrated in slightly less developed, and the venter is not as narrowly Fig. 34A. rounded (Fig. 34B). The suture line of holotype UMNH IP 3253, drawn at Type locality and horizon. – Granite Mountain North, bed 12.5 mm diameter, shows a median saddle that is higher 17; Camp Canyon Member of Chainman Formation, Caly- than half of the external lobe depth; it is encased by asym- girtyoceras arcticum Biozone. metrically subdivided prongs of the external lobe (Fig. 33B). The dorsal of the two new prongs is the more Material. – The holotype and 34 paratypes; conch diameter prominent and asymmetric. Both prongs are acute and sep- up to 16 mm. arated by a subacute saddle. On the flank follow the tongue-shaped, elongate ventrolateral saddle and the ad- Diagnosis. – Species of Dimorphoceras with a discoidal ventive lobe, which is also tongue-shaped, slightly asym- conch (ww/dm = 0.50–0.55) and narrowly rounded venter. metric, and blunt at its base.

154 Dieter Korn & Alan L. Titus • Goniatites Zone (middle Mississippian) ammonoids, Nevada and Utah

Table 17. Conch dimensions (in mm) and proportions for reference specimens of Dimorphoceras rileyi sp. nov.

dm ww wh uw ah ww/dm ww/wh uw/dm WER IZR HT UMNH IP 3253 15.7 8.1 9.1 0.3 5.8 0.51 0.89 0.02 2.50 0.36 PT MB.C.12007.1 11.5 5.5 6.4 0.0 3.9 0.48 0.86 0.00 2.28 0.39 PT UMNH IP 3246 10.2 5.3 6.0 0.2 3.8 0.52 0.89 0.02 2.52 0.37 HT UMNH IP 3237 10.0 4.9 5.8 0.1 3.6 0.49 0.85 0.00 2.41 0.38

Paratype UMNH IP 3248 shows, at 10.2 mm diameter, Ningxia; gorbovense: Paradimorphoceras gorbovense a very similar suture line that differs from the larger speci- Kusina & Yatskov, 1988, p. 33; Novaya Zemlya; heterodi- men in the lower median saddle and the rounded saddle be- visum: Paradimorphoceras heterodivisum Ruan, 1981, tween the secondary prongs of the external lobe (Fig. 33A). p. 208; Guangxi; hodsoni: Dimorphoceras (Metadimor- phoceras) hodsoni Moore, 1958, p. 223; Ireland; inflatum: Discussion. – Dimorphoceras rileyi differs from D. worki Dimorphoceras inflatum Moore, 1939, p. 116; Lancashire; and D. kathleenae in the blunt adventive lobe and the lenticulare: Metadimorphoceras lenticulare Yang, 1986, V-shaped secondary prongs of the external lobe. D. gilbert- p. 264; Ningxia; mangeri: Metadimorphoceras mangeri soni has a strongly asymmetric adventive lobe, in contrast sp. nov.; Antler Foreland Basin; moorei: Dimorphoceras to the tongue-shaped lobe in D. rileyi. The stratigraphically moorei Hodson, 1954, p. 362; Ireland; orientale: Paradi- much older, late Chadian D. leagramense has a very simi- morphoceras orientale Ruzhencev & Bogoslovskaya, lar suture line, but differs in the much more lenticular 1971, p. 195; South Urals; pix: Metadimorphoceras pix conch at comparable diameters (ww/dm = 0.25–0.30) at Korn, 1997, p. 46; South Portugal; pseudodiscrepans: Di- 10–12 mm diameter in contrast to 0.50–0.55 in D. rileyi. morphoceras pseudodiscrepans Moore, 1939, p. 112; Lan- D. algens from the Kuna Formation of Alaska possesses cashire; ribblense: Dimorphoceras ribblense Moore, 1936, rounded external and adventive lobes. p. 190; Lancashire; richardsi: Metadimorphoceras richard- si sp. nov.; Antler Foreland Basin; saharicum: Dimorpho- ceras looneyi var. saharica Dollé, 1912, p. 250; Western Subfamily Glyphiolobinae Ruzhencev & Bogoslovskaya, Algeria; saleswheelense: Dimorphoceras saleswheelense 1969 Moore, 1939, p. 118; Lancashire; saundersi: Metadimor- phoceras saundersi Manger & Quinn, 1972, p. 311; Arkan- Subfamily definition. – Dimorphoceratidae with a subdivi- sas; splendidum: Goniatites splendidus Brown, 1841, ded adventive lobe. p. 215; Yorkshire; strictum: Paradimorphoceras strictum Ruzhencev & Bogoslovskaya, 1971, p. 196; South Urals; Included genera. – Glyphiolobus Gordon, 1965; Metadi- subdivisum: Metadimorphoceras subdivisum Manger & morphoceras Moore, 1958; Paradimorphoceras Ruzhen- Quinn, 1972, p. 312; Arkansas; tongxinense: Paradimor- cev, 1947; Sulcodimorphoceras Manger & Pareyn, 1979; phoceras tongxinense Gao, 1983, p. 464; Ningxia; varians: Anthracoceratites Ramsbottom, 1970; Currieoceras Man- Dimorphoceras varians Moore, 1939, p. 113; Lancashire; ger, 1988 [synonym of Glyphiolobus Gordon, 1965]. wiswellense: Dimorphoceras wiswellense Moore, 1939, p. 115; Lancashire.

Genus Metadimorphoceras Moore, 1958 Discussion. – Metadimorphoceras has an almost global distribution and 23 valid species are listed in the AMMON Type species. – Goniatites splendidus Brown, 1841 (origi- database (Korn & Ilg 2010); these derive from a wide stra- nal designation). tigraphic interval ranging from the middle Late Viséan Go- niatites crenistria interval to the Kinderscoutian R1 Zone in Genus definition. – Glyphiolobinae with a subdivision of Europe (Moore 1939) and even in the Yeadonian G1 Zone in the external lobe into more than two tertiary lobes. Arkansas (Manger 1988). Separation of species is almost completely based on suture line characters. The European Included species. – aguinosum: Metadimorphoceras agui- and North African species have been separated by Korn & nosum Korn & Ebbighausen, 2008, p. 94; Moroccan Me- Ebbighausen (2008) into three groups, based on the subdivi- seta; complex: Dimorphoceras complex Moore, 1939, sion of the adventive lobe. According to this scheme, both p. 116; Yorkshire; denticulatum: Dimorphoceras denticu- species from the Camp Canyon Member belong in the first latum Schmidt, 1925, p. 601; Rhenish Mountains; disloba- group, which is characterized by a simple subdivision of the tum: Metadimorphoceras dislobatum Yang, 1986, p. 265; adventive lobe into two similarly sized prongs.

155 Bulletin of Geosciences • Vol. 86, 1, 2011

A B

Figure 35. Metadimorphoceras mangeri sp. nov. • A – holotype UMNH IP 3273 from bed 6 (sample 01UTMI-3) of South Burbank Hills; × 5. • B – paratype UMNH IP 3281 from bed 4 (sample 01UTMI-2) of South Burbank Hills; × 5.

Table 18. Conch dimensions (in mm) and proportions for reference specimens of Metadimorphoceras mangeri sp. nov.

dm ww wh uw ah ww/dm ww/wh uw/dm WER IZR PT UMNH IP 3279 13.5 6.2 8.0 0.0 4.8 0.46 0.77 0.00 2.43 0.40 HT UMNH IP 3273 8.6 4.6 4.9 0.0 3.2 0.54 0.94 0.00 2.49 0.36 PT UMNH IP 3278 5.4 3.7 2.9 0.0 – 0.69 1.28 0.00 – –

Metadimorphoceras mangeri sp. nov. cus, the flanks converge markedly, and the venter is nar- Figures 35, 36D rowly rounded. Shell remains show a smooth surface, and the internal mould possesses weak impressions of bicon- Derivation of name. – After Walter M. Manger, to honour vex growth lines (Fig. 35A). his contributions to Carboniferous ammonoid palaeonto- The suture line of paratype UMNH IP 3280 (5.2 mm logy and particularly the dimorphoceratids. ww) shows the narrow, parallel-sided median saddle and the subdivided external lobe (Fig. 36D). The sides of the exter- Holotype. – Specimen UMNH IP 3273, illustrated in nal lobe possess two asymmetric prongs, both showing in- Fig. 35A. cipient further subdivision, with the dorsal prong being wider than the ventral one. The adventive lobe is subdivided, Type locality and horizon. – South Burbank Hills, bed 6; but the saddle between the two secondary lobes is very low. Camp Canyon Member of Chainman Formation, Girtyoce- ras primum Biozone. Discussion. – Metadimorphoceras mangeri has one of the simplest suture line of the genus. The adventive lobe has Material. – The holotype and ten paratypes; conch diame- just reached the stage of secondary subdivision, and the ex- ter up to 13 mm. ternal lobe is still rather simple. This combination suggests a phylogenetic position near the base of the Metadimor- Diagnosis. – Species of Metadimorphoceras with a discoi- phoceras evolutionary branch (Manger, 1988). The incom- dal conch (ww/dm = 0.45–0.55) and narrowly rounded plete subdivision of the adventive lobe is a criterion that se- venter. Shell is almost smooth, with very fine biconvex parates M. mangeri from all other species of the genus. growth lines. Suture line with very high median saddle, sub- acute secondary prongs of the external lobe, rounded ven- trolateral saddle, and asymmetric bifid adventive lobe with Metadimorphoceras richardsi sp. nov. a low saddle between the secondary, subacute prongs. Figures 36A–C, 37

Description. – Holotype UMNH IP 3273 is the best- Derivation of name. – After Barry Richards, who helped to preserved specimen of the material. It has a diameter of collect the material. 8.6 mm and is discoidal (ww/dm = 0.54) with a closed um- bilicus and a high aperture (WER = 2.50). The conch is, as Holotype. – Specimen UMNH IP 3290, illustrated in characteristic for dimorphoceratids, thickest at the umbili- Fig. 37B.

156 Dieter Korn & Alan L. Titus • Goniatites Zone (middle Mississippian) ammonoids, Nevada and Utah

Type locality and horizon. – Hamilton Canyon, bed 44; Camp Canyon Member of Chainman Formation, Goniati- tes eganensis Biozone.

Material. – The holotype and eight paratypes; conch dia- meter up to 15 mm. D Diagnosis. – Species of Metadimorphoceras with a discoi- dal conch (ww/dm = 0.50–0.55) and narrowly rounded venter. Shell almost smooth, with very fine biconvex growth lines. Suture line with very high median saddle, acute secondary prongs of the external lobe with incipient further subdivision, rounded ventrolateral saddle, and asymmetric bifid adventive lobe with acute prongs. C

Description. – The two well-preserved specimens UMNH IP 3292 and UMNH IP 3290 show, at 13–14.5 mm conch diameter, very similar proportions, with a ww/dm ratio of B little more than 0.50, a closed umbilicus, and a high aper- ture (WER nearly 2.60). The conch shape is thus characte- ristic for the genus (Fig. 37). The smaller specimens UMNH IP 3294 (9.7 mm diame- A ter), MB.C.12010.2 (8.7 mm diameter), and MB.C.12010.1 (8 mm diameter) are thickly lenticular conchs (ww/dm = Figure 36. Species of Metadimorphoceras.•A–Metadimorphoceras 0.52–0.55) with a high aperture (WER = 2.55–2.60). As char- richardsi sp. nov, suture line of paratype MB.C.12010.1 from bed 25 of South Burbank Hills, at 3.6 mm ww; × 10.•B–Metadimorphoceras acteristic for dimorphoceratids, the conch is thickest near the richardsi sp. nov, suture line of holotype UMNH IP 3290 from bed 44 almost closed, funnel-shaped umbilicus. The three specimens (sample 07NVWP-3) of Hamilton Canyon, at 4.8 mm ww; × 10. are smooth internal moulds of the phragmocone; they show •C–Metadimorphoceras richardsi sp. nov, suture line of paratype barely visible rhythmic folds of strengthened growth lines. UMNH IP 3293 from bed 44 (sample 95NVWP-15) of Hamilton Canyon, Shell ornament is preserved in some of the specimens. at9.4mmwh;×6.•D–Metadimorphoceras mangeri sp. nov, suture line of paratype UMNH IP 3280 from bed 4 (sample 01UTMI-2) of South Specimen UMNH IP 3290 appears to be completely smooth, Burbank Hills, at 5.2 mm ww; × 8. but the internal mould shows faint traces of impressed biconvex growth lines (Fig. 37B). Specimen MB.C.12010.3 shows a three-dimensionally preserved phragmocone of (Fig. 36B, C). The asymmetry implies an incipient further 9.3 mm diameter and the impression of the somewhat subdivision of the dorsal prong. Both prongs are acute. The crushed body chamber. The steinkern of the phragmocone is ventrolateral saddle is narrow and high, and on the flank almost smooth, but remains of the shell show delicate spiral follows the bifid adventive lobe, in which the outer prong is lines. These spirals are best visible on the impressed body less deep as the inner one. chamber, where they are more prominent than the biconvex, Smaller specimens such as paratype MB.C.12010.1 periodically strengthened growth lines. (drawn at 3.6 mm ww) possess a moderately high median The suture line is best visible in paratype UMNH IP 3293 saddle (reaching half of the external lobe depth). It is en- (9.4 mm wh) and holotype UMNH IP 3290 (4.8 mm ww). cased by the almost symmetric secondary prongs of the ex- Both show a typical tongue-shaped median saddle, bor- ternal lobe, which are subdivided into two almost symmet- dered by the subdivided sides of the external lobe, in which ric, acute tertiary prongs. On the flank follow an almost the dorsal prong is a little bit wider than the ventral prong symmetric, slightly inflated ventrolateral saddle and a bifid

Table 19. Conch dimensions (in mm) and proportions for reference specimens of Metadimorphoceras richardsi sp. nov.

dm ww wh uw ah ww/dm ww/wh uw/dm WER IZR PT UMNH IP 3292 14.7 7.1 9.1 0.2 5.5 0.49 0.79 0.01 2.56 0.39 HT UMNH IP 3290 13.2 6.8 8.3 0.2 5.0 0.52 0.82 0.02 2.58 0.40 HT UMNH IP 3294 9.7 5.3 5.5 0.1 3.6 0.55 0.96 0.01 2.55 0.34 PT MB.C.12010.2 8.7 4.7 5.3 0.1 3.3 0.54 0.89 0.01 2.60 0.38 PT MB.C.12010.1 8.0 4.2 4.5 0.2 – 0.52 0.93 0.02 – –

157 Bulletin of Geosciences • Vol. 86, 1, 2011

A B

Figure 37. Metadimorphoceras richardsi sp. nov. • A – paratype UMNH IP 3292 from bed 25 (sample 07UTMI-1) of South Burbank Hills; × 5. • B – holotype UMNH IP 3290 from bed 44 (sample 07NVWP-3) of Hamilton Canyon; × 5. adventive lobe with two acute prongs of the same size bylundi sp. nov.; Antler Foreland Basin; compressum: Ka- (Fig. 36A). zakhoceras compressum Liang & Gao, 1963, p. 565; Guan- gxi [synonym of K. yanshini]; hawkinsi: Neodimorphoce- Discussion. – Metadimorphoceras richardsi belongs to the ras hawkinsi Moore, 1930, p. 168; Lancashire; lenticulum: simple-sutured species of the genus (Manger 1988), show- Kazakhoceras lenticulum Ruan, 1981, p. 212; Guangxi; ing a degree of complexity comparable to the late Asbian scaliger: Dimorphoceras ?scaliger Schmidt, 1934, p. 458; (British P1a Zone) M. pseudodiscrepans (Moore, 1939), Rhenish Mountains; yanshini: Kazakhoceras yanshini which, however, already shows a further subdivision of the Ruzhencev, 1947, p. 522; South Urals. external lobe. A similar complexity stage, but also with a weak tertiary subdivision of the external lobe, is visible in Discussion. – Kazakhoceras was so far only recorded from the early Brigantian M. hodsoni Moore, 1958. This shows stratigraphically much younger horizons. The genus is rather that M. richardsi obviously represents a very early stage in frequent in beds around the Viséan-Serpukhovian bound- the diversification of the genus Metadimorphoceras. ary of the South Urals (Ruzhencev & Bogoslovskaya 1971), but has also rarely been recorded from late Brigan- tian beds of North England (Moore 1930) and the Rhenish Family Berkhoceratidae Librovitch, 1957 Mountains (Korn 1988). With the new finds, the range of Kazakhoceras is pulled down markedly into the Asbian. Family definition. – Dimorphocerataceae with a low, con- verging median saddle and a strongly converging ventrola- teral saddle. Kazakhoceras bylundi sp. nov. Figures 38, 39 Included genera. – Kazakhoceras Ruzhencev, 1947; Ber- khoceras Librovitch, 1957 [synonym of Kazakhoceras Derivation of name. – After Kevin Bylund who helped to Ruzhencev, 1947]. collect the material.

Holotype. – Specimen UMNH IP 3309, illustrated in Genus Kazakhoceras Ruzhencev, 1947 Fig. 38A.

Type species. – Kazakhoceras yanshini Ruzhencev, 1947 Type locality and horizon. – Middle Confusion Range 1, (original designation). bed 10; Camp Canyon Member of Chainman Formation, Calygirtyoceras arcticum Biozone. Genus definition. – As for the family. Material. – The holotype and eight paratypes; conch dia- Included species. – armstrongi: Neodimorphoceras arm- meter up to 45 mm. strongi Currie, 1954, p. 593; Dunbartonshire; boreale: Berkhoceras boreale Librovitch, 1957, p. 260; Novaya Diagnosis. – Species of Kazakhoceras with a thinly discoi- Zemlya [synonym of K. yanshini]; bylundi: Kazakhoceras dal conch (ww/dm = 0.35) and a very narrowly rounded

158 Dieter Korn & Alan L. Titus • Goniatites Zone (middle Mississippian) ammonoids, Nevada and Utah

B

A

C

Figure 38. Kazakhoceras bylundi sp.nov.•A–holotype UMNH IP 3309 from bed 10 (sample 05UTMI-3) of South Confusion Range 1; × 1.5. • B – paratype UMNH IP 3308 from bed 9 (sample 97UTMI-13) of Jensen Wash; × 1.5.•C–paratype UMNH IP 3311 from bed 17 (sample sample 94UTJU-1) of Granite Mountain South; × 3. venter. Shell almost smooth, with very fine biconvex (Fig. 38A). It is a lentil-shaped specimen (ww/dm = growth lines. Suture line with rounded ventrolateral sad- 0.35) with very few attached shell remains. The conch is dles. thickest near the closed umbilicus, the flanks are almost flat and converge towards the very narrowly rounded Description. – Paratypes UMNH IP 3310 and UMNH IP venter. The aperture is very high, resulting in a whorl ex- 3306 were sectioned for the study of the conch ontogeny pansion rate of 2.58. (Fig. 39A, B). It shows a globular conch early in onto- The smaller paratype UMNH IP 3308 has 31 mm conch geny, followed by a growth stage in which the whorls be- diameter and is similar to the larger specimen, but the aper- come laterally compressed and the conch more slender. ture is even higher (WER = 2.83). Shell remains are pre- The umbilicus is slightly opened in this early stage up to served in this specimen; they show very fine, strongly 3 mm conch diameter, but closes rapidly. At 6 mm diame- biconvex growth lines with equally high dorsolateral and ter, the conch is already discoidal (ww/dm = 0.50) with ventrolateral projections and a very deep ventral sinus a high aperture (WER = 2.40) and a narrowly rounded (Fig. 38B). venter. The umbilical margin is rounded in this whorl. Al- Suture lines were drawn from paratype UMNH IP 3311 ready on half of a volution later, at 10.5 mm diameter, the (Fig. 39C) at 13 mm and from holotype UMNH IP 3309 umbilical margin has become flattened and gives the um- (Fig. 39D) at 32 mm diameter. The adult suture line is typi- bilicus a funnel-like shape. Acceleration of aperture heigh- cal for the genus with a secondarily subdivided external tening is continuing at this stage, the whorl expansion lobe. The primary prong of the external lobe is lanceolate rate amounts 2.88 here (Fig. 39E–G). At the same time, and deeper than the secondary prong; both are separated by the flanks become slightly flattened and converge to- a narrow tongue-shaped saddle. The ventrolateral saddle is wards the continuously narrowing venter. Another half of almost symmetric, at least in its upper part, and has a semi- a volution later (17 mm diameter), the whorl cross section circular top. On the flank follows the asymmetric is very similar, but the relative height of the aperture de- adventive lobe with a convex ventral and a concave dorsal creases (WER = 2.74). flank. The well-preserved specimens allow the study of growth stages between approximately 20 and 44 mm. Discussion. – Kazakhoceras bylundi has a similar conch The largest of them, holotype UMNH IP 3309, has like K. hawkinsi and K. yanshini, but differs in ornament 44 mm conch diameter and is fully chambered and suture details. K. hawkinsi and K. yanshini have an

159 Bulletin of Geosciences • Vol. 86, 1, 2011

E

D F

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G

A B

Figure 39. Kazakhoceras bylundi sp.nov.•A–cross section of paratype UMNH IP 3310 from bed 10 (sample 05UTMI-3) of South Confusion Range 1;×2.5.•B–cross section of paratype UMNH IP 3306 from bed 17 (sample 07UTJU-1) of Granite Mountain South; × 2.5.•C–suture line of paratype UMNH IP 3311 from bed 17 (sample sample 94UTJU-1) of Granite Mountain South, at 13.2 mm diameter, 5.4 mm ww, 8.7 mm wh; × 5.0. • D – suture line of holotype UMNH IP 3309 from bed 10 (sample 05UTMI-3) of South Confusion Range 1, at 31.1 mm diameter, 11.1 mm ww, 19.1 mm wh; × 5.0. • E–G – ontogenetic development of the conch width index (ww/dm), umbilical width index (uw/dm), whorl width index (ww/wh), and whorl expansion rate (WER) of all available specimens. ornament with spiral lines in contrast to K. bylundi, where hausen, 2010; Habadraitinae Korn, Bockwinkel & Ebbig- only very fine growth lines are present. The suture line, hausen, 2010; Antegoniatitinae Korn, Bockwinkel & Eb- which is very similar in the three species, offers further cri- bighausen, 2010. teria for a separation: K. hawkinsi and K. yanshini have a subacute ventrolateral saddle, particularly regarding the Subfamily Goniatitinae de Haan, 1825 first, whereas in K. bylundi the ventrolateral saddles are rounded. Included genera. – Goniatites de Haan, 1825; Hypergonia- tites Ruzhencev & Bogoslovskaya, 1970; Goniatitella Korn, 1988; Glyphioceras Hyatt, 1884 [synonym of Goni- Superfamily Goniatitaceae de Haan, 1825 atites de Haan, 1825]; Sphenoceras Foord, 1903 [synonym of Goniatites de Haan, 1825]. Included families. – Goniatitidae de Haan, 1825; Agathice- ratidae von Arthaber, 1911; Delepinoceratidae Ruzhencev, 1957; Glyphioceratidae Hyatt, 1884 [synonym of Goniati- Genus Goniatites de Haan, 1825 tidae de Haan, 1825]. Type species.–Conchiliolithus Nautilites (sphaericus) Family Goniatitidae de Haan, 1825 Martin, 1809 [nomen nudum], = Ammonites sphaericus Sowerby, 1814 (Opinion 420 ICZN, 1956). Included subfamilies. – Goniatitinae de Haan, 1825; Arns- bergitinae Korn & Ebbighausen, 2008; Sygambritinae Genus definition. – Goniatitinae with subinvolute inner Korn, 1988; Progoniatitinae Korn, Bockwinkel & Ebbig- whorls; the umbilicus becomes closed in early ontogeny.

160 Dieter Korn & Alan L. Titus • Goniatites Zone (middle Mississippian) ammonoids, Nevada and Utah

Table 20. Conch ontogeny (Fig. 39) of Kazakhoceras bylundi sp. nov. dm conch shape whorl cross section shape aperture 2 mm thickly pachyconic; involute weakly depressed; strongly embracing (ww/wh ~ 1.35; IZR ~ 0.45) moderate (WER ~ 1.80) (ww/dm ~ 0.75; uw/dm ~ 0.16) 10 mm thinly discoidal; involute weakly compressed; strongly embracing (ww/wh ~ 0.70; IZR ~ 0.30) very high (WER ~ 2.90) (ww/dm ~ 0.42; uw/dm ~ 0.05) 20 mm thinly discoidal; involute weakly compressed; strongly embracing (ww/wh ~ 0.60; IZR ~ 0.35) very high (WER ~ 2.70) (ww/dm ~ 0.37; uw/dm ~ 0.03) 45 mm thinly discoidal; involute weakly compressed; strongly embracing (ww/wh ~ 0.60; IZR ~ 0.35) very high (WER ~ 2.60) (ww/dm ~ 0.35; uw/dm ~ 0.00)

Table 21. Conch dimensions (in mm) and proportions for reference specimens of Kazakhoceras bylundi sp. nov.

dm ww wh uw ah ww/dm ww/wh uw/dm WER IZR HT UMNH IP 3309 44.1 15.6 26.4 0.3 16.7 0.35 0.59 0.01 2.58 0.37 PT UMNH IP 3308 31.5 11.1 19.4 0.4 12.8 0.35 0.57 0.01 2.83 0.34 PT UMNH IP 3306 18.6 7.0 11.1 0.8 7.3 0.37 0.63 0.04 2.70 0.34 PT UMNH IP 3310 17.3 6.2 10.4 0.5 6.9 0.36 0.60 0.03 2.74 0.34 PT UMNH IP 3311 13.2 5.4 8.7 0.2 5.3 0.41 0.62 0.02 2.79 0.39

External lobe V-shaped, very narrow or narrow, usually 1880, p. 110; Belgium; lazarus: Goniatites lazarus Korn, with slightly curved flanks. Klug & Mapes, 2005, p. 359; Anti-Atlas; lepidus: Goniati- tes lepidus Brandon & Hodson, 1984, p. 21; Ireland [nomen Included species. – americanus: Goniatites americanus nudum]; maximus: Goniatites maximus Bisat, 1934, Gordon, 1971, p. C41; Utah; antiquatus: Goniatites anti- p. 298; Yorkshire [homonym of Goniatites maximus quatus Bisat, 1934, p. 302; Yorkshire; asturicus: Glyphio- Münster, 1832; synonym of G. moorei]; moorei: Goniati- ceras sphaericum var. asturica Frech, 1902, p. 84; Canta- tes moorei Weyer, 1972, p. 180; Yorkshire; multiliratus: brian Mountains; constractus: Goniatites constractus Liang Goniatites multiliratus Gordon, 1962, p. 356; Oklahoma; & Wang, 1991, p. 93; Xinjiang; crenifalcatus: Goniatites olsysya: Goniatites olsysya Korn, 2001, p. 228; North crenifalcatus crenifalcatus Bogoslovskaya, 1966, p. 40; Urals; praestriatus: Glyphioceras crenistria var. praestri- South Urals; crenistria: Goniatites crenistria Phillips, ata Schmidt, 1925, p. 566; Rhenish Mountains [synonym 1836, p. 234; Yorkshire; deceptus: Goniatites deceptus sp. of G. spirifer]; pseudosphaericus: Goniatites pseudospha- nov.; Antler Foreland Basin, Nevada-Utah; dinckleyensis: ericus Brandon & Hodson, 1984, p. 21; Ireland [nomen nu- Goniatites crenistria dinckleyense Bisat, 1928, p. 132; dum]; rodioni: Goniatites rodioni Korn & Ebbighausen, Lancashire [synonym of G. fimbriatus]; eganensis: Gonia- 2006, p. 24; Anti-Atlas; schmidtianus: Goniatites crenistria tites eganensis sp. nov.; Antler Foreland Basin, schmidtianus Nicolaus, 1963, p. 103; Rhenish Mountains Nevada-Utah; evelinae: Goniatites evelinae Korn & Eb- [synonym of G. hudsoni]; shimanskyi: Goniatites shiman- bighausen, 2006, p. 29; Anti-Atlas; fimbriatus: Glyphioce- skyi Bogoslovskaya, 1966, p. 43; South Urals; sphaericus: ras fimbriatus Foord & Crick, 1897, p. 303; Yorkshire or Conchiliolithus Nautilites sphaericus Martin, 1809, pl. 7; Lancashire; fuhrmanni: Goniatites fuhrmanni Schinde- Derbyshire [nomen nudum; synonym of G. sphaericus So- wolf, 1951, p. 71; Harz; gerberi: Goniatites gerberi Korn werby, 1814]; sphaericus: Goniatites sphaericus Sowerby, & Ebbighausen, 2006, p. 27; Anti-Atlas; globiformis: Go- 1814, p. 116; Derbyshire; sphaeroides: Goniatites crenifal- niatites (Goniatites) stenumbilicatus globiformis Kull- catus sphaeroides Bogoslovskaya, 1966, p. 43; South Urals; mann, 1961, p. 294; Cantabrian Mountains; globoides: spirifer: Goniatites spirifer Roemer, 1850, p. 51; Harz; sten- Glyphioceras crenistria var. globoides Schmidt, 1925, umbilicatus: Goniatites (Goniatites) stenumbilicatus sten- p. 566; Rhenish Mountains [synonym of G. crenistria]; umbilicatus Kullmann, 1961, p. 290; Cantabrian Mountains; grandis: Goniatites grandis Liang & Wang, 1991, p. 95; sowerbyi: Goniatites sowerbyi sp. nov.; Antler Foreland Ba- Xinjiang; hudsoni: Goniatites hudsoni Bisat, 1934, p. 303; sin, Nevada-Utah; tympanus: Goniatites tympanus Korn, Lancashire; intermedius: Glyphioceras intermedium Ko- Bockwinkel & Ebbighausen, 2007, p. 142; Anti-Atlas; bold, 1933, p. 487; Harz [homonym of Goniatites interme- undatus: Goniatites undatus Kumpera, 1975, p. 13; North dius Münster, 1832; synonym of G. fimbriatus]; interrup- Moravia; vesica: Goniatites vesica Phillips, 1836, p. 43; tus: Ammonites interruptus de Koninck, 1844, p. 580; Yorkshire [synonym of G. crenistria]; wedberensis: Goni- Belgium; involutus: Goniatites involutus de Koninck, atites wedberensis Bisat, 1934, p. 304; Yorkshire.

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A B

C D

Figure 40. Goniatites americanus Gordon, 1971 from the Calygirtyoceras arcticum Biozone of localities in Utah.•A–specimen UMNH IP 3450 from bed 17 (sample 07UTJU-1) of Granite Mountain North; × 1.5. • B – specimen MB.C.12013.1 from bed 15 of Granite Mountain South; × 1.5. • C – speci- men MB.C.12016.1 from bed 8 of Middle Confusion Range 1; × 1.5.•D–specimen UMNH IP 3451 from bed 17 (sample 07UTJU-1) of Granite Moun- tain North; × 1.5.

Discussion. – Goniatites is a diverse genus with an almost 1965 Goniatites aff. G. crenistria Phillips; Gordon, p. 187 global distribution, encompassing nearly 40 species, of (part), text-figs 44A, B. which about 15 are synonyms. As discussed by Korn et al. 1970 Goniatites americanus Gordon; Gordon, p. 821 (part) (2005), the genus appears suddenly in the late Asbian with [nomen nudum], text-fig. 2 (Great Basin Region an almost global distribution. A possible predecessor, Pro- only). goniatites, has a similar conch and sutural morphology, but 1971 Goniatites americanus Gordon; p. C41, text-fig. 3. occurs in the early Late Tournaisian (Korn et al. 2003b, 1972 Goniatites crenistria Phillips; Drahovzal, p. 36, 2010). There is no record of intermediate forms in the latest text-fig. 17A. Tournaisian or Early and Middle Viséan. 1984 Goniatites americanus Gordon; Webster et al.,p.31, All species of Goniatites display a very similar conch text-fig. 12. geometry, conch ontogeny, and suture line, which do not 1995 Goniatites cf. crenistria Phillips; Sadlick, p. 12. allow the subdivision into distinct morphological groups. A putative criterion for a subdivision of the genus, e.g. the Holotype. – Specimen USNM 170616, illustrated by Gor- ornament possessing or lacking spiral lines, cannot be used don (1971) in text-figures 3l–o. since it is obviously not an apomorphic character of a dis- tinct clade but occurs iteratively in the genus. Type locality and horizon. – North-eastern slope of Granite Mountain; Camp Canyon Member of Chainman Forma- tion, Calygirtyoceras arcticum Biozone. Goniatites americanus Gordon, 1971 Figures 40–44 Material. – 892 specimens; conch diameter up to 61 mm. The largest specimens are still fully chambered, so that a 1957 Goniatites crenistria Phillips; Gordon, p. 42, pl. 5, maximum diameter of the species of about 90 mm can be figs 1–8, 12–16 (not figs 9–11), text-fig. 17A–D. estimated.

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A B

CD

Figure 41. Goniatites americanus Gordon, 1971 from the Girtyoceras primum Biozone of localities in Utah.•A–specimen MB.C.12025.1 from bed 25 of Granite Mountain South; × 1.0.•B–specimen MB.C.12017.1 from bed 12 of Middle Confusion Range 1; × 2.5.•C–specimen UMNH IP 3754 from bed 25 (sample 94UTJU-9) of Granite Mountain South; × 1.0. • D – specimen UMNH IP 3526 from bed 13 (sample 97UTMI-12) of Jensen Wash; × 2.0.

Diagnosis. – Goniatites with globular to spindle-shaped 43A–F) were produced to study the ontogenetic changes conch between 2 and 8 mm diameter (ww/dm = 0.90–1.15), and intraspecific variability of the species. The morpho- thickly pachyconic to globular conch (ww/dm = 0.80–1.00) metric plots (Figs 42E–G, 43M–O) show that two distinct at 20 mm diameter and pachyconic conch (ww/dm = ontogenetic intervals can be separated, of which the first 0.65–0.85) at 30 mm diameter. Umbilicus moderate in one ranges up to about 6 mm conch diameter. This stage is early ontogeny (uw/dm = 0.20–0.35 at 2 mm diameter) and characterized by an increasing conch width from ww/dm = very narrow in all stages larger than 4 mm diameter 0.75–0.90 at 1 mm diameter to ww/dm = 0.90–1.15 at (uw/dm = 0.01–0.10). Umbilical wall incurved in late 6 mm diameter. At the same time, the umbilicus, which is growth stages. Aperture low (WER = 1.60–1.90) at 30 mm slightly opened in the early juvenile stage (uw/dm = diameter. Ornament with crenulated, slightly biconvex and 0.25–0.35 at 2 mm diameter), is almost completely closed. rursiradiate growth-lines; external sinus shallow. Some The second growth interval, beginning at about 6 mm dia- very fine spiral lines around the umbilicus. Suture line at meter, leads to a more slender adult conch shape. The 25 mm conch diameter with very narrow or narrow exter- ww/dm ratio is reduced to 0.65–0.85 at 30 mm diameter, nal lobe (0.50 of the external lobe depth; 1.15 of the ventro- and the umbilicus remains almost closed (uw/dm = lateral saddle width), and low median saddle (0.30 of the 0.00–0.05). In the second growth interval, the aperture be- external lobe depth). External lobe Y-shaped with very nar- comes slightly higher, expressed in a whorl expansion rate row, V-shaped prongs; ventrolateral saddle acute. between 1.60 and 1.90 at 20–30 mm diameter. The morphometric plots demonstrate wide morpholog- Description. – Goniatites americanus is represented by a ical range within the material, particularly in the ww/dm large number of well-preserved specimens, and a total of ratio and the whorl expansion rate (Figs 43M, O, 44R) be- 12 cross sections (some of them illustrated in Figs 42A and tween growth stages of 7 and 30 mm conch diameter. In the

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D

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B G

A

Figure 42. Goniatites americanus Gordon, 1971 from the Calygirtyoceras arcticum Biozone of localities in Utah.•A–cross section of specimen MB.C.12013.2 from bed 15 of Granite Mountain South; × 2.5.•B–suture line of specimen MB.C.12016.2 from bed 8 of Middle Confusion Range, at 7.7mmdm,8.8mmww;×5.0.•C–suture line of specimen MB.C.12016.3 from bed 8 of Middle Confusion Range, at 12.0 mm ww; × 5.0.•D–growth line course of specimen MB.C.12013.1 from bed 15 of Granite Mountain South, at 20.3 mm diameter, 17.5 mm wh, 10.1 mm ww; × 4.0. • E–G – ontogenetic development of the conch width index (ww/dm), umbilical width index (uw/dm), and whorl expansion rate (WER) of all available specimens. ww/dm ratio, the position of the middle two quartiles lies ers are included. The uw/dm ratio has a range of variability always in a narrow zone near the lower end, meaning that of 0.15 up to 8 mm conch diameter, and later decreasing skewing is particularly well expressed towards thicker because of the known reasons. In the WER plot, a variabil- conchs. The uw/dm ratio appears to be less variable, but ity range of 0.30 is expressed above 3 mm diameter. this is obviously due to the fact that an almost closed umbi- Specimen MB.C.12014.4 (Fig. 43F) from bed 25 licus does not allow much geometric variance. In the (Girtyoceras primum Biozone) of Granite Mountain, with ww/dm ratio, the range of variability is 0.25 throughout on- a maximum diameter of nearly 26 mm, can be regarded as a togeny, and sometimes even higher when some rare outli- characteristic morphological representative of the species

Figure 43. Goniatites americanus Gordon, 1971 from the Girtyoceras primum Biozone of localities in Utah.•A–cross section of specimen MB.C.12019.1 from bed 10 of Middle Confusion Range 2; × 2.5. • B – cross section of specimen MB.C.12019.2 from bed 10 of Middle Confusion Range 2; × 2.5.•C–cross section of specimen MB.C.12014.1 from bed 25 of South Granite Mountain; × 2.5.•D–cross section of specimen MB.C.12014.2 from bed 25 of South Granite Mountain; × 2.5.•E–cross section of specimen MB.C.12014.3 from bed 25 of South Granite Mountain; ×2.5.•F–cross section of specimen MB.C.12014.4 from bed 25 of South Granite Mountain; × 2.5.•G–suture line of specimen UMNH IP 3757 from bed 25 (sample 94UTJU-9) of Granite Mountain South, at 19.9 mm diameter, 17.1 mm ww, 10.5 mm wh; × 3.0.•H–suture line of specimen MB.C.12017.2 from bed 12 of Middle Confusion Range 1, at 24.6 mm diameter, 19.6 mm ww, 11.2 mm wh; × 3.0.•I–suture line of specimen UMNH IP 3392 from bed 25 (sample 05UTJU-12) of Granite Mountain South, at 25.6 mm diameter, 20.9 mm ww, 12.2 mm wh; × 3.0.•J–suture line of specimen UMNH IP 3754 from bed 25 (sample 05UTJU-12) of Granite Mountain South, at 51.5 mm diameter, 34.2 mm ww, 26.0 mm wh; × 2.0.•K–growth line course of specimen UMNH IP 3755 from bed 25 (sample 94UTJU-9) of Granite Mountain South, at 24.9 mm diameter, 19.6 mm ww, 13.6 mm wh; × 4.0. • L – growth line course of specimen UMNH IP 3754 from bed 25 (sample 05UTJU-12) of Granite Mountain South, at 46.5 mm diameter, 30.8 mm ww, 21.0 mm wh; × 2.0. • M–O – ontogenetic development of the conch width index (ww/dm), umbilical width index (uw/dm), and whorl expansion rate (WER) of all available specimens.

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165 Bulletin of Geosciences • Vol. 86, 1, 2011

Table 22. Conch ontogeny (Figs 42, 43) of Goniatites americanus Gordon, 1971. dm conch shape whorl cross section shape aperture 1.5 mm globular; subinvolute or subevolute strongly depressed; strongly embracing low (WER = 1.60–1.75) (ww/dm = 0.85–1.00; uw/dm = 0.25–0.35) (ww/wh = 2.10–2.50; IZR = 0.40–045) 5 mm globular or spindle-shaped; involute strongly depressed; very strongly embracing low or moderate (WER = 1.50–1.85) (ww/dm = 0.95–1.15; uw/dm = 0.05–0.15) (ww/wh = 2.10–2.50; IZR = 0.50–0.60) 10 mm globular or spindle-shaped; involute moderately depressed; very strongly embracing low or moderate (WER = 1.65–2.00) (ww/dm = 0.85–1.25; uw/dm = 0.00–0.10) (ww/wh = 1.60–1.95; IZR = 0.50–0.60) 25 mm thickly pachyconic or globular; involute weakly or mod. depr.; very strongly embracing low to moderate (WER = 1.50–1.85) (ww/dm = 0.75–1.00; uw/dm = 0.00–0.10) (ww/wh = 1.35–1.85; IZR = 0.50–0.60) 55 mm pachyconic; involute weakly depressed; very strongly embracing low (WER = 1.60–1.65) (ww/dm = 0.65–0.75; uw/dm = 0.05–0.10) (ww/wh = 1.25–1.45; IZR = 0.50–0.60)

Table 23. Conch dimensions (in mm) and proportions for reference specimens of Goniatites americanus Gordon, 1971 from the Calygirtyoceras arcticum Biozone.

dm ww wh uw ah ww/dm ww/wh uw/dm WER IZR UMNH IP 3450 37.4 31.1 20.5 3.3 8.3 0.83 1.52 0.09 1.66 0.59 UMNH IP 3451 33.5 25.3 18.9 1.9 8.3 0.75 1.34 0.06 1.76 0.56 MB.C.12016.1 29.3 23.4 13.8 1.6 7.1 0.80 1.70 0.05 1.74 0.48 MB.C.12013.1 25.5 20.4 14.2 1.1 6.3 0.80 1.43 0.04 1.76 0.56 MB.C.12013.2 24.0 19.9 13.1 0.6 5.6 0.83 1.52 0.03 1.71 0.57

Table 24. Conch dimensions (in mm) and proportions for reference specimens of Goniatites americanus Gordon, 1971 from the Girtyoceras primum Biozone.

dm ww wh uw ah ww/dm ww/wh uw/dm WER IZR MB.C.12025.1 60.1 41.1 28.8 6.5 12.9 0.68 1.43 0.11 1.62 0.55 UMNH IP 3754 53.2 34.4 25.6 4.9 11.5 0.65 1.34 0.09 1.62 0.55 MB.C.12014.4 25.9 22.0 13.5 1.8 5.3 0.85 1.63 0.07 1.58 0.61 UMNH IP 3367 25.6 19.4 13.9 0.9 6.2 0.76 1.39 0.03 1.74 0.55 UMNH IP 3756 22.2 17.0 12.6 0.5 5.9 0.77 1.35 0.02 1.86 0.53 UMNH IP 3526 22.1 18.5 11.5 0.8 5.3 0.84 1.61 0.04 1.72 0.54 MB.C.12019.1 18.9 16.3 10.6 0.2 4.4 0.86 1.54 0.01 1.69 0.59 MB.C.12019.2 18.1 14.8 10.0 0.5 4.7 0.82 1.48 0.03 1.84 0.53 MB.C.12014.1 17.8 15.6 9.8 0.4 4.2 0.88 1.59 0.02 1.71 0.57 MB.C.12014.3 17.6 14.4 10.0 0.2 4.5 0.81 1.44 0.01 1.79 0.55 MB.C.12014.2 16.4 14.8 8.4 1.5 3.7 0.90 1.77 0.09 1.66 0.56 MB.C.12014.6 16.4 13.4 8.8 0.7 4.0 0.82 1.52 0.04 1.75 0.55 MB.C.12017.1 14.3 14.3 8.3 0.7 3.1 0.99 1.72 0.05 1.63 0.63 MB.C.12014.5 13.3 11.6 7.2 0.6 3.3 0.88 1.61 0.04 1.78 0.54 because it ranges, in its conch proportions, in the centre of shown in the last volution. The conch is widest at the umbi- the morphological spectrum. It shows similar whorl cross licus. sections throughout ontogeny, with a C-shaped outline, Specimens MB.C.12014.3 (17.5 mm diameter; Fig. 43E) with whorls embracing the preceding to a high degree (IZR and MB.C.12014.2 (16.5 mm diameter; Fig. 43D), also = 0.56–0.62 between 2 and 26 mm diameter), and with a from Granite Mountain bed 25, represent the more slender whorl expansion rate oscillating between 1.55 and 1.75. and more globular spectrum of conch geometry. Apart All whorls up to 13 mm diameter show a broadly rounded from the ww/dm ratio, these specimens have different ap- umbilical margin and a convex umbilical wall. Later in on- ertural heights, causing a whorl expansion rate of 1.80 in togeny, the umbilical margin becomes more pronounced the slender specimen MB.C.12014.3 and 1.65 in the globu- and the umbilical wall is flattened or even incurved, as lar specimen MB.C.12014.2.

166 Dieter Korn & Alan L. Titus • Goniatites Zone (middle Mississippian) ammonoids, Nevada and Utah

Figure 44. Goniatites americanus Gordon, 1971, box and whiskers dia- grams showing the variability within the A B conch width index (ww/dm), umbilical width index (uw/dm), and whorl expan- sion rate (WER) during ontogeny. White boxes refer to the middle two quartiles, black bars refer to the total range within each D(log) unit. • A, B – specimens from the higher horizons (Girtyoceras primum Biozone). • C, D – specimens from the lower horizons (Calygirtyoceras arcticum Biozone). C D

Table 25. Suture line proportions (Figs 42, 43) for Goniatites americanus Gordon, 1971. specimen at dm EL w/d EL/VLS EL/AL MS h VLS w/h remarks UMNH IP 3754 51.6 0.60 1.17 1.36 0.46 0.51 E lobe Y-shaped UMNH IP 3392 25.6 0.51 1.14 0.92 0.31 0.45 VL saddle almost symmetric, acute MB.C.12017.2 24.6 0.49 1.05 0.85 0.29 0.46 VL saddle almost symmetric, acute UMNH IP 3757 19.9 0.40 1.12 0.70 0.32 0.36 VL saddle narrowly rounded

At 53 mm conch diameter, UMNH IP 3754 (Fig. 41C) ventral projection with a very shallow sinus. A shallow is one of the largest available specimens. It is still fully constriction, running parallel to the growth lines, is visi- chambered. This thinly pachyconic conch (ww/dm = 0.65) ble on the internal mould. has a very narrow umbilicus (uw/dm = 0.09) and a low ap- Suture lines were drawn from specimens in different erture (WER = 1.62). The venter is broadly rounded, and growth stages. The suture line of the large specimen the umbilical wall is incurved. Most of the specimen is cov- UMNH IP 3754 (51.5 mm conch diameter; Fig. 43J) has a ered with shell that shows the ornament composed of slightly Y-shaped external lobe with diverging flanks and a strongly crenulated growth lines with rursiradiate convex median saddle of 0.46 height of the E lobe depth. The course and very fine spiral lines best visible around the um- prongs of the external lobe are very narrow. The acute bilicus. ventrolateral saddle has a symmetric shape except for the UMNH IP 3526 (Fig. 41D) is a beautifully preserved curvature in its dorsal flank. This curvature of the ventral specimen with 22 mm conch diameter. The conch is thickly flank of the adventive lobe occurs in the upper third and pachyconic (ww/dm = 0.84) with an almost closed umbili- causes an indistinct asymmetry of the V-shaped adventive cus (uw/dm = 0.04) and a low aperture (WER = 1.72). It is lobe. entirely covered with shell that shows the strongly Suture lines of smaller specimens are more diagnostic, crenulated, slightly biconvex growth lines with a rather particularly because they can be compared with specimens high dorsolateral projection and a very shallow ventral si- of the same size of other species. Specimens nus. MB.C.12017.2 and UMNH IP 3392 (both approximately Smaller specimens show wide variability in their 25 mm diameter; Fig. 43H, I) show similar suture lines conch shapes. MB.C.12017.1 (14 mm diameter; with a Y-shaped external lobe, in which the upper part di- Fig. 41B), for instance, has an almost spherical shape verges stronger. The external lobe is narrower than the (ww/dm = 0.99) with a very narrow umbilicus and a low adventive lobe, and it has very narrow prongs. A median aperture (WER = 1.63). The shell shows wide-standing saddle is raised to 0.3 of the external lobe depth. The crenulated growth lines that possess a dominant ventrolateral saddle is almost symmetric and acute, and the dorsolateral projection, a shallow lateral sinus and a broad adventive lobe is V-shaped. The difference between the

167 Bulletin of Geosciences • Vol. 86, 1, 2011 two suture lines is the fact that in UMNH IP 3392 the flanks Goniatites deceptus sp. nov. of the lobes are stronger curved than in MB.C.12017.2. Figures 45–50

Discussion. – An overemphasis of ornamental criteria for 1970 Goniatites multiliratus Gordon; Gordon (part), p. 821, species distinction of North American Goniatites has led to text-fig. 2 (Great Basin portion only). previous workers confusing stratigraphically and suturally 1971 Goniatites multiliratus Gordon; Gordon, p. C40, distinct forms such as G. americanus and G. eganensis (see text-fig. 1. synonymy for details). Sutural criteria can be readily used 1984 Goniatites multiliratus Gordon; Webster et al.,p.31, to differentiate G. americanus from all other North Ameri- text-fig. 12. can species of crenistriate Goniatites. The median saddle 1995 Goniatites multiliratus Gordon; Sadlick, p. 3, of G. americanus reaches only 30 percent of the depth text-figs 12, 13. of the external lobe, in contrast to the stratigraphically younger species G. eganensis and G. sowerbyi, in which Derivation of name. – From Lat. deceptior = fake, since the this value reaches 40 percent. We want to emphasize that material of this species has, in earlier studies, erroneously true G. americanus has never been found east of the Great been attributed to G. multiliratus. Basin. The European species G. hudsoni bears the closest Holotype. – Specimen UMNH IP 3937, illustrated in resemblance to G. americanus, and separation can only Fig. 45B. be achieved when the material is very well preserved. G. hudsoni occurs, like G. americanus, with a wide mor- Type locality and horizon. – Jensen Wash, bed 28; Camp phological spectrum including slender and also stout Canyon Member of Chainman Formation, Goniatites de- variants (see Korn & Ebbighausen 2008, text-fig. 22), ceptus Biozone. which are connected by a continuous range of intermedi- ate morphologies. The only criterion for separating the Material. – 266 specimens; conch diameter up to 61 mm. two species is the conspicuous, narrow dorsolateral pro- jection of the growth lines in G. hudsoni. This projection Diagnosis. – Goniatites with globular conch between 2 and is also present in G. americanus, but is much wider and 8 mm diameter (ww/dm = 0.85–1.05), pachyconic conch lower. (ww/dm = 0.70–0.80) at 20 mm diameter, and thinly pa- G. rodioni from the Anti-Atlas of Morocco shows also chyconic conch (ww/dm = 0.65–0.70) at 30 mm diameter. some resemblance with G. americanus, particularly in Umbilicus moderate in early ontogeny (uw/dm = conch shape and also shell ornament with a dorsolateral 0.20–0.30 at 2 mm diameter) and very narrow or nearly projection of the growth lines, but differs in the much nar- closed in all stages larger than 4 mm diameter (uw/dm = rower external lobe. 0.01–0.10). Umbilical wall flattened in late growth stages. Because the species has such an extended stratigraphic Aperture low or moderate (WER = 1.65–1.85 at 30 mm range in the Chainman Formation, we tested the hypothesis diameter). Ornament with crenulated, slightly biconvex that all specimens belong to only one species. Strati- and rectiradiate growth-lines; external sinus shallow. graphically older (e.g. bed 17 of Granite Mountain = 180–200 very fine spiral lines. Suture line at 25 mm conch Calygirtyoceras arcticum Zone) and younger (e.g. bed 25 diameter with narrow external lobe (0.50–0.55 of the exter- of Granite Mountain = Girtyoceras primum Zone) material nal lobe depth; 1.25 of the ventrolateral saddle width), and was analysed separately with respect to ontogenetic trajec- moderately low median saddle (0.40 of the external lobe tories and intraspecific variability (Fig. 44). Results show depth). External lobe Y-shaped with narrow, V-shaped that that the material represents a large morphological prongs; ventrolateral saddle subangular. spectrum that cannot be separated into different species. Likewise, the suture lines and shell ornament of these Description. – The biometric plots show that there is only stratigraphically disparate occurrences cannot be subdi- minor intraspecific variability, and that ontogenetic chan- vided. ges are less well developed as in other species of the genus

Figure 45. Goniatites deceptus sp. nov. from localities in Utah, slender variants of the species.•A–paratype UMNH IP 3945 from bed 19 (sample 01UTMI-43) of Conger Mountain West; × 1.0.•B–holotype UMNH IP 3937 from bed 28 of Jensen Wash; × 1.25.•C–paratype UMNH IP 3934 from bed 28 (sample 93UTMI-27) of Jensen Wash; × 1.25.•D–paratype UMNH IP 3946 from bed 19 (sample 01UTMI-43) of Conger Mountain West; × 1.5. • E – paratype UMNH IP 3868 from bed 35 (sample 94UTJU-10) of Granite Mountain North; × 2.0. • F – paratype UMNH IP 3938 from bed 28 of Jensen Wash; × 2.0.•G–paratype UMNH IP 3869 from bed 35 (sample 94UTJU-10) of Granite Mountain North; × 2.0.•H–paratype UMNH IP 3870 from bed 35 (sample 94UTJU-10) of Granite Mountain North; × 2.0.

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reaches 2.00 at 7 mm diameter. Thereafter, the conch be- comes continuously more slender and is thinly pachyconic at 30 mm diameter (ww/dm = 0.65–0.70). The sectioned large paratype MB.C.12026.1 shows the entire conch ontogeny up to a diameter of 54 mm diameter (Fig. 49). It has a globular conch up to 6 mm diameter and thereafter shows continuous lateral compression. Above about 20 mm conch diameter, the umbilical wall begins to flatten, and above 30 mm diameter it is slightly incurved in its section. Sections made from the Duckwater material are similar but differ slightly in that they show more strongly converging flanks (Fig. 50B, C). Two smaller sectioned paratypes, UMNH IP 3871 and A UMNH IP 3872 (Fig. 48A, B), both nearly 20 mm in diam- eter, are very similar to each other and differ mainly in the width of the conch. They show the ontogenetic transforma- tion from the ventrally depressed, kidney-shaped whorl cross section to the C-shaped section in later ontogenetic stages, the almost perfect closure of the umbilicus, and the rounded convex umbilical wall. Holotype UMNH IP 3937 is a well-preserved specimen of 40 mm conch diameter (Fig. 45B); it is fully chambered and almost entirely covered with the shell. It is thickly pachyconic and involute (ww/dm = 0.68; uw/dm = 0.06) with a narrowly rounded umbilical margin and a broadly rounded venter. The shell is decorated with faint spiral B lines, approximately 200 from umbilicus to umbilicus, which are arranged in irregular distances and which are stronger around the umbilicus and the inner flanks. The growth lines are much finer than the spiral lines; they ex- tend with a biconvex course, forming low lateral projec- tions and a rather deep ventral sinus. Paratype UMNH IP 3945 (55 mm diameter; Fig. 45A) represents the adult stage of the species. It is thickly discoidal (ww/dm = 0.59) with a very narrow umbilicus (uw/dm = 0.07) and is a slender variant of the species. The specimen has a low aperture (WER = 1.74). Some parts are covered with shell, which display a delicate ornament of C fine biconvex growth lines and extremely fine spiral orna- ment that is missing in a narrow zone around the umbilicus Figure 46. Goniatites deceptus sp. nov. from localities in Utah; stouter and more prominent on the venter. variants of the species. • A – paratype UMNH IP 3839 from bed 19 (sam- Paratype UMNH IP 3933 (49 mm diameter; Fig. 46B) ple 01UTMI-43) of Conger Mountain West; × 1.0.•B–paratype UMNH from Jensen Wash is a stout variant of the species (ww/dm IP 3933 from bed 28 (sample 93UTMI-27) of Jensen Wash; × 1.0. = 0.74), with a characteristic wide and slightly depressed • C – paratype MB.C.12026.2 from bed 33 of Granite Mountain North; venter. The spiral lines are similarly strong on flanks and × 2.0. venter. Paratype UMNH IP 3934 (39 mm diameter; Fig. 45C), (Figs 48G–I, 50H–J). The early juvenile stage is globular at also from Jensen Wash, is more slender (ww/dm = 0.63). 2 mm diameter (ww/dm = 0.85–1.00) with a moderately In its dorsal portion, the shell is covered by patches of wide umbilicus (uw/dm = 0.20–0.30), followed by a wrinkle layer, which themselves are covered by an almost growth interval with a slight increase of the ww/dm index smooth shell layer with traces of exceedingly fine spiral of 0.85–0.93 between 4 and 8 mm diameter and an almost lines. complete closure of the umbilicus. The aperture becomes Paratype UMNH IP 3868 (Fig. 45E) at 26 mm conch higher during this interval and the whorl expansion rate diameter, is a moderate-sized individual. It is thinly

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Figure 47. Goniatites deceptus sp. nov. from localities in Nevada.•A–paratype UMNH IP 3845 from bed 4 (sample 93NVNY-1) of Duckwater Hills; × 1.5.•B–paratype UMNH IP 3846 from bed 4 (sample 93NVNY-1) of Duckwater Hills; ×1.5.•C–paratype UMNH IP 3847 from bed 4 (sample 93NVNY-1) of Duckwater Hills; × 2.0.•D–paratype MB.C.12027.1 from Cathedral Canyon; × 2.0.•E–paratype MB.C.12027.2 from Cathedral Canyon; × 1.5. E pachyconic (ww/dm = 0.67) with an almost closed umbilicus and a shallow ventral sinus. Juvenile specimens such as (uw/dm = 0.04) and a rather high aperture (WER = 1.92). UMNH IP 3875 (8 mm diameter) are thickly pachyconic Shell is well preserved in specimen UMNH IP 3868; showing and show almost straight constrictions. fine spiral lines and delicate, slightly biconvex growth lines. Paratype MB.C.12026.2 (25 mm diameter; Fig. 46C) The internal mould of the smaller paratype UMNH IP 3869 belongs to the thicker, more cuboid end of the morphologi- (22.5 mm dm; Fig. 45G) has a few irregularly spaced con- cal spectrum (ww/dm = 0.80), which exhibit an almost strictions running parallel to the growth lines. completely closed umbilicus. This specimen’s shell is or- UMNH IP 3870 is a small paratype (almost 20 mm di- namented with 180 fine and regularly spaced spiral lines ameter; Fig. 45H) that shows similar conch proportions. and very fine growth lines. Specimen MB.C.12026.2 has Growth lines and constrictions of the internal mould have a constrictions on the internal mould, which stand almost very shallow lateral sinus, a low ventrolateral projection, precisely 90° apart.

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Figure 48. Goniatites deceptus sp. nov. from bed 35 (sample 94UTJU-10) of Granite Mountain North (Utah).•A–cross section of paratype UMNH IP 3871; × 2.5.•B–cross section of paratype UMNH IP 3872; × 2.5.•C–growth line course of paratype UMNH IP 3870, at 17.0 mm diameter; × 5.0. • D – suture line of paratype UMNH IP 3873, at 7.7 mm diameter, 8.8 mm ww; × 5.0.•E–suture line of paratype UMNH IP 3874, at 12.0 mm ww; × 5.0. • F – suture line of paratype UMNH IP 3870, at 15.0 mm diameter, 12.4 mm ww; × 5.0. • G–I – ontogenetic development of the conch width index (ww/dm), umbilical width index (uw/dm), and whorl expansion rate (WER) of all available specimens.

Three suture lines have been drawn of the material from Nevada and Utah, respectively, of which one (UMNH IP 3873; Fig. 48D) is from a juvenile of 8 mm diameter and does not show specific characters. The suture lines of UMNH IP 3874 and UMNH IP 3870 (Fig. 48E, F) are from approxi- mately 15 mm diameter and differ slightly from each other. The external lobe is subparallel in the first and V-shaped in the second, slightly larger specimen. Both have a narrow, subangular ventrolateral saddle and a wider, asymmetric adventive lobe with sinuous flanks. In UMNH IP 3870, the external lobe has a width of 0.55 of its depth, and the median saddle reaches 40 per cent of the external lobe depth. The suture lines of the material from Duckwater were obtained from diameters between 19 and 37 mm and show similar outlines. The suture line of paratype UMNH IP 3849 (Fig. 50G) has, at 37 mm conch diameter, a V-shaped external lobe, in which the flanks are almost straight and diverge slowly. The median saddle is raised to a height of 0.45 of the E lobe depth. The ventrolateral saddle is rather narrow and asymmetric; it is subacute at its top and appears to be dorsally inclined. The adventive Figure 49. Goniatites deceptus sp. nov., cross section of paratype lobe is as wide as the external lobe and has strongly MB.C.12026.1 from bed 33 of Granite Mountain North; × 1.5. curved flanks.

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Figure 50. Goniatites deceptus sp. nov. from localities in Nevada.•A–dorsal view of paratype MB.C.12027.2 from Cathedral Canyon; × 2.0.•B–cross section of paratype MB.C.12028.1 from bed 4 of Duckwater Hills; × 2.5. • C – cross section of paratype MB.C.12028.2 from bed 4 of Duckwater Hills; × 2.5. • D – growth line course of paratype MB.C.12027.3 from Cathedral Canyon, at 24.8 mm diameter, 20.3 mm ww, 13.2 mm wh; × 3.0.•E–suture line of paratype UMNH IP 3848 from bed 4 (sample 93NVNY-1) of Duckwater Hills, at 19.0 mm diameter, 14.3 mm ww, 9.8 mm wh; × 5.0.•F–suture line of paratype UMNH IP 3846 from bed 4 (sample 93NVNY-1) of Duckwater Hills, at 28.1 mm diameter, 20.6 mm ww, 14.4 mm wh; × 5.0.•G–suture line of paratype UMNH IP 3849 from bed 4 (sample 93NVNY-1) of Duckwater Hills, at 36.8 mm diameter, 27.6 mm ww, 19.5 mm wh; × 5.0. • H–J – ontogenetic development of the conch width index (ww/dm), umbilical width index (uw/dm), and whorl expansion rate (WER) of all available specimens.

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Table 26. Conch ontogeny (Figs 48, 50) of Goniatites deceptus sp. nov. dm conch shape whorl cross section shape aperture 1.5 mm globular; subinvolute or subevolute strongly depressed; strongly embracing low or moderate (WER = 1.60–1.80) (ww/dm = 0.85–1.00; uw/dm = 0.25–0.35) (ww/wh = 2.10–2.50; IZR = 0.35–045) 5 mm globular; involute moderately depressed; very strongly embracing moderate (WER = 1.75–1.95) (ww/dm = 0.90–1.00; uw/dm = 0.03–0.10) (ww/wh = 1.60–1.90; IZR = 0.50–0.60) 10 mm thickly pachyconic or globular; involute weakly to mod. depressed; very strongly embracing low or moderate (WER = 1.60–1.95) (ww/dm = 0.75–0.95; uw/dm = 0.00–0.08) (ww/wh = 1.40–1.80; IZR = 0.50–0.60) 25 mm thinly or thickly pachyconic; involute weakly or mod. depressed; very strongly embracing low or moderate (WER = 1.65–1.95) (ww/dm = 0.65–0.75; uw/dm = 0.00–0.08) (ww/wh = 1.20–1.60; IZR = 0.50–0.60) 55 mm thinly pachyconic; involute weakly depressed; very strongly embracing low (WER = 1.65–1.75) (ww/dm = 0.60–0.65; uw/dm = 0.05–0.10) (ww/wh = 1.10–1.20; IZR = 0.50–0.60)

Table 27. Conch dimensions (in mm) and proportions for reference specimens of Goniatites deceptus sp. nov. from localities in Utah.

dm ww wh uw ah ww/dm ww/wh uw/dm WER IZR PT UMNH IP 3939 60.9 36.4 30.8 4.7 14.0 0.60 1.18 0.08 1.69 0.55 PT UMNH IP 3945 54.9 32.2 28.4 3.7 13.3 0.59 1.13 0.07 1.74 0.53 PT UMNH IP 3933 48.8 36.0 25.4 4.8 12.4 0.74 1.42 0.10 1.80 0.51 HT UMNH IP 3937 40.3 27.3 20.8 2.5 10.0 0.68 1.31 0.06 1.77 0.52 PT UMNH IP 3934 39.1 24.8 21.4 3.0 9.9 0.63 1.16 0.08 1.79 0.54 PT UMNH IP 3946 37.7 25.3 19.4 2.5 8.9 0.67 1.30 0.07 1.72 0.54 PT UMNH IP 3868 25.8 17.3 14.2 1.0 7.2 0.67 1.22 0.04 1.92 0.49 PT MB.C.12026.2 25.4 20.1 12.6 1.9 5.7 0.79 1.59 0.07 1.66 0.55 PT UMNH IP 3938 24.0 17.0 12.6 1.4 5.8 0.71 1.35 0.06 1.74 0.54 PT UMNH IP 3869 22.4 15.5 11.7 1.0 5.7 0.69 1.32 0.05 1.79 0.51 PT UMNH IP 3870 19.5 14.6 10.4 0.9 5.4 0.75 1.40 0.05 1.91 0.48

Table 28. Conch dimensions (in mm) and proportions for reference specimens of Goniatites deceptus sp. nov. from localities in Nevada.

dm ww wh uw ah ww/dm ww/wh uw/dm WER IZR PT MB.C.12027.2 41.0 26.1 20.8 2.3 9.9 0.64 1.25 0.06 1.74 0.52 PT UMNH IP 3845 40.5 26.3 21.9 2.7 9.8 0.65 1.20 0.07 1.74 0.55 PT UMNH IP 4020 37.3 23.7 20.2 2.8 – 0.64 1.17 0.08 – – PT UMNH IP 3846 30.3 20.5 15.0 2.3 7.5 0.68 1.37 0.08 1.76 0.50 PT MB.C.12027.1 25.7 19.2 13.8 1.4 5.9 0.75 1.39 0.05 1.68 0.57 PT UMNH IP 3847 20.8 16.3 9.8 1.0 4.7 0.78 1.67 0.05 1.66 0.52

Table 29. Suture line proportions (Figs 48, 50) for Goniatites deceptus sp. nov. specimen at dm EL w/d EL/VLS EL/AL MS h VLS w/h remarks UMNH IP 3849 36.8 0.55 1.64 1.03 0.45 0.33 E lobe V-shaped UMNH IP 3846 28.1 0.49 1.24 0.81 0.44 0.40 VL saddle asymmetric UMNH IP 3848 19.0 0.47 1.20 0.91 0.39 0.39 VL saddle almost symmetric UMNH IP 3870 15.0 0.58 1.29 0.86 0.40 0.45 E lobe V-shaped UMNH IP 3874 14.0 0.54 1.37 0.77 0.39 0.40 E lobe slightly Y-shaped

Discussion. – Specimens of G. deceptus sp. nov. have pre- delicate spiral lines, but differ in their conch ontogeny and viously been attributed to G. multiliratus Gordon, 1962, suture line. G. deceptus has a narrower external lobe a species described from the Caney Shale of Oklahoma but (width/height ratio = 0.50–0.55 in G. deceptus but 0.65 in also occurring in Texas and Arkansas (Gordon 1965). Both G. multiliratus at 25 mm conch diameter) and a narrower species do possess similar shell ornament with numerous umbilicus in the juvenile stage. There is also clear strati-

174 Dieter Korn & Alan L. Titus • Goniatites Zone (middle Mississippian) ammonoids, Nevada and Utah graphic separation of G. deceptus and G. multiliratus, with 1970 Goniatites americanus Gordon; Gordon, p. 818 (re- the former occurring immediately below G. eganensis ferring to Arkansas material only), text-fig. 2 (Ozark n. sp., and the latter above. Furthermore, the older species Plateau portion only). G. deceptus does not appear to have ever been collected 1972 Goniatites crenistria Phillips; Drahovzal, p. 20 (part), from east of the Great Basin region. figs 3, 4, pl. I, figs 2–4. G. eganensis sp. nov. is very similar in conch shape and suture line, but lacks spiral ornament. Derivation of name. – After the Egan Range, where the type locality is.

Goniatites eganensis sp. nov. Holotype. – Specimen UMNH IP 4021, illustrated in Fig. 51B. Figures 51–54 Type locality and horizon. – Trough Springs Canyon, bed 6 1897 Glyphioceras incisum Hyatt; Smith, p. 111, pls (sample 93NVLI-3); Camp Canyon Member of Chainman XIII–XV. Formation, Goniatites eganensis Biozone. 1903 Goniatites crenistria Phillips; Smith, p. 68 (part), pl. XIV, figs 1–12, pl. XV, figs 1–8, pl. XVI, Material. – 76 specimens; conch diameter up to 40 mm. figs 1a–j, pl. XXVI, figs 1–3 (not 4, 5). 1911 Goniatites crenistria Phillips; Girty, p. 99, pl. XV, Diagnosis. – Goniatites with a globular conch between 2 figs 8, 9. and 8 mm diameter (ww/dm = 0.85–0.90) and thickly pa- 1949 Goniatites choctawensis Shumard; Miller et al., chyconic conch (ww/dm = 0.75–0.80) at 20 mm diameter. p. 608, pl. 99, figs 7, 8. Umbilicus moderate in early ontogeny (uw/dm = 1965 Goniatites aff. G. crenistria Phillips; Gordon (part), 0.20–0.30 at 2 mm diameter) and very narrow in all stages p. 187, pl. 18, figs 1–6, 46A–C. larger than 4 mm diameter (uw/dm = 0.02–0.10). Umbili- 1965 Goniatites crenistria Phillips; King, p. 42. cal wall convexly rounded in all stages. Aperture low or

A B

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Figure 51. Goniatites eganensis sp. nov. from localities in Nevada. • A – paratype UMNH IP 4020 from bed 6 (sample 93NVLI-3) of Trough Springs Canyon; × 1.5.•B–holotype UMNH IP 4021 from bed 6 (sample 93NVLI-3) of Trough Springs Canyon; × 1.5. • C – paratype UMNH IP 4010 from bed 44 (sample 07NVWP-3) of Hamilton Canyon; × 1.5. • D – paratype MB.C.12030.1 from bed 44 of Hamilton Canyon; × 2.5.

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Figure 52. Goniatites eganensis sp. nov. from bed 25 (sample 01UTMI-5) of South Burbank Hills (Utah). • A – paratype UMNH IP 4003; × 2.5. • B – paratype UMNH IP 4004; × 2.5.

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Figure 53. Goniatites eganensis sp. nov. from localities in Nevada.•A–cross section of specimen UMNH IP 4022 from bed 6 (sample 93NVLI-3) of Trough Springs Canyon; × 2.5.•B–suture line of paratype MB.C.12030.2 from bed 44 of Hamilton Canyon, at 15.3 mm diameter, 12.2 mm ww, 7.3 mm wh; × 3.0. • C – suture line of paratype MB.C.12030.1 from bed 44 of Hamilton Canyon, at 15.7 mm diameter, 13.0 mm ww, 7.5 mm wh; × 3.0. •D–su- ture line of paratype MB.C.12030.3 from bed 44 of Hamilton Canyon, at 20.1 mm diameter, 16.0 mm ww, 10.4 mm wh; × 3.0.•E–suture line of paratype UMNH IP 4010 from bed 6 (sample 93NVLI-3) of Trough Springs Canyon, at 24.6 mm ww, 14.3 mm wh; × 3.0. • F–H – ontogenetic development of the conch width index (ww/dm), umbilical width index (uw/dm), and whorl expansion rate (WER) of all available specimens. moderately high (WER = 1.70–1.80 at 20 mm diameter). ternal lobe depth). External lobe V-shaped with narrow, Ornament with crenulated, slightly biconvex and rectiradi- V-shaped prongs; ventrolateral saddle subangular. ate growth-lines; external sinus shallow. Suture line at 25 mm conch diameter with narrow external lobe (0.55 of Description. – The species shows ontogenetic changes ty- the external lobe depth; 1.25 of the ventrolateral saddle pical for the genus (Figs 48G–I, 50F–H). The early juvenile width), and moderately low median saddle (0.40 of the ex- stage has an open umbilicus, but this is closed rapidly and

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Figure 54. Goniatites eganensis sp. nov. from bed 25 (sample 07UTMI-1) of South Burbank Hills (Utah).•A–cross section of paratype UMNH IP 3997; × 2.5.•B–cross section of paratype UMNH IP 4005; × 2.5.•C–suture line of paratype UMNH IP 4006, at 7.2 mm diameter, 7.3 mm ww, 3.8 mm wh; × 4.0. • D – suture line of paratype UMNH IP 4004, at 17.3 mm diameter, 14.4 mm ww, 9.2 mm wh; × 4.0.•E–growth line course of paratype UMNH IP 4004, at 14.8 mm diameter, 12.9 mm ww, 9.0 mm wh; × 4.0. • F–H – ontogenetic development of the conch width index (ww/dm), umbilical width in- dex (uw/dm), and whorl expansion rate (WER) of all available specimens. already above 4 mm diameter, the uw/dm ratio is lower with small portions of shell preserved. It is thinly than 0.10. There is a juvenile ontogenetic trend towards a pachyconic and involute (ww/dm = 0.64; uw/dm = 0.06) thicker conch, with a maximum ww/dm ratio of 0.90–1.00 with strongly converging flanks and a broadly rounded between 2 and 8 mm diameter. Thereafter, the conch beco- venter. The aperture is moderately high (WER = 1.78). The mes more slender and the ww/dm ratio amounts to 0.74 at shell surface displays strongly crenulated growth lines, 24 mm diameter. The aperture has a constant opening rate which have a shallow lateral sinus, a low ventrolateral pro- throughout ontogeny; limited fluctuations occur between jection, and a shallow ventral sinus. 1.70 and 1.90. The largest available specimen from South Burbank The largest sectioned paratype UMNH IP 4022 Hills (paratype UMNH IP 4007) is 23.5 mm in diameter and (Fig. 53A) from Trough Springs Canyon has a maximum is thickly pachyconic (ww/dm = 0.74). The umbilicus is conch diameter of 28 mm has a globular conch shape up to closed and the aperture is narrow (WER = 1.74). It is partly about 8 mm dm. Thereafter, the conch becomes continu- testiferous and shows growth lines that run concavo-convex ously more slender, being thinly pachyconic at 28 mm dm across the flanks and venter and form a moderately deep (ww/dm = 0.66). ventral sinus. These growth lines are intensely crenulated A sectioned paratype, UMNH IP 4005 (Fig. 54B), from and rather coarse with a spacing of about 0.5 mm. South Burbank Hills has a maximum diameter of 15 mm Smaller specimens, such as paratypes UMNH IP 4003 and displays six whorls. It is a section of a ball-shaped and UMNH IP 4004 (20, resp. 18 mm diameter; Fig. 52A, B), conch in which all whorls show a similar section. The um- have a similar but somewhat more globular form (ww/dm = bilical wall, flanks, and venter are broadly rounded, and the 0.80–0.82) and display an ornament with coarser growth umbilical opening is similar throughout ontogeny. lines having an almost straight course across the flanks and Holotype UMNH IP 4021 (Fig. 51B) from Trough venter. These specimens also show irregularly arranged Springs has a conch diameter of 37 mm and is fully septate constrictions on the internal mould.

177 Bulletin of Geosciences • Vol. 86, 1, 2011

Table 30. Conch ontogeny (Figs 53, 54) of Goniatites eganensis sp. nov. dm conch shape whorl cross section shape aperture 1.5 mm globular; subinvolute or subevolute strongly depressed; strongly embracing low or moderate (WER = 1.60–1.80) (ww/dm = 0.85–0.95; uw/dm = 0.25–0.35) (ww/wh = 2.00–2.50; IZR = 0.40–045) 5 mm globular; involute moderately depressed; very strongly embracing low or moderate (WER = 1.70–1.90) (ww/dm = 0.90–1.00; uw/dm = 0.03–0.10) (ww/wh = 1.60–1.90; IZR = 0.50–0.60) 10 mm thickly pachyconic or globular; involute weakly to mod. depressed; very strongly embracing moderate (WER = 1.75–2.00) (ww/dm = 0.85–0.95; uw/dm = 0.00–0.08) (ww/wh = 1.40–1.80; IZR = 0.50–0.60) 25 mm thinly or thickly pachyconic; involute weakly or mod. depressed; very strongly embracing moderate (WER = 1.75–2.00) (ww/dm = 0.65–0.80; uw/dm = 0.00–0.08) (ww/wh = 1.10–1.55; IZR = 0.50–0.60) 40 mm thinly or thickly pachyconic; involute weakly depressed; very strongly embracing moderate (WER ~ 1.80) (ww/dm = 0.65–0.75; uw/dm = 0.05–0.10) (ww/wh = 1.20–1.40; IZR = 0.50–0.60)

Table 31. Conch dimensions (in mm) and proportions for reference specimens of Goniatites eganensis sp. nov. from localities in Nevada.

dm ww wh uw ah ww/dm ww/wh uw/dm WER IZR PT UMNH IP 4010 39.0 28.5 21.2 3.3 – 0.73 1.35 0.08 – – PT UMNH IP 4020 37.3 23.7 20.2 2.8 – 0.64 1.17 0.08 – – HT UMNH IP 4021 37.0 23.6 19.5 2.2 9.3 0.64 1.21 0.06 1.78 0.52 PT MB.C.12030.1 19.0 15.4 10.7 1.1 4.5 0.81 1.44 0.06 1.73 0.58 PT MB.C.12030.2 16.3 13.0 8.3 0.9 4.1 0.80 1.57 0.06 1.78 0.51

Table 32. Conch dimensions (in mm) and proportions for reference specimens of Goniatites eganensis sp. nov. from localities in Utah.

dm ww wh uw ah ww/dm ww/wh uw/dm WER IZR PT UMNH IP 4003 20.1 16.1 10.6 1.0 4.8 0.80 1.52 0.05 1.73 0.55 PT UMNH IP 4004 18.5 15.2 9.2 1.0 4.6 0.82 1.65 0.05 1.76 0.51 PT UMNH IP 4006 7.7 7.4 3.8 0.6 2.0 0.97 1.98 0.08 1.84 0.46

Table 33. Suture line proportions (Figs 53, 54) for Goniatites eganensis sp. nov.

specimen at dm EL w/d EL/VLS EL/AL MS h VLS w/h remarks UMNH IP 4010 34.0 0.57 1.32 1.22 0.44 0.43 VL saddle tectiform, flanks sinuous MB.C.12030.3 20.1 0.47 1.24 0.72 0.38 0.38 VL saddle acute UMNH IP 4004 17.3 0.57 1.29 1.01 0.35 0.44 VL saddle acute MB.C.12030.1 15.7 0.46 1.11 0.93 0.33 0.41 VL saddle subacute MB.C.12030.2 15.3 0.52 1.29 0.85 0.38 0.40 VL saddle subacute

Paratype UMNH IP 4010 shows the adult suture line, Discussion. – Goniatites eganensis sp. nov. is, in conch which possesses a V-shaped external lobe with sinuous shape, conch ontogeny, conch variability, and suture line, flanks and a median saddle that is lower than half the depth very similar to G. deceptus sp. nov. The two species differ of the E lobe. The ventrolateral saddle is almost symmetric mainly in the absence of spiral ornament in G. eganensis. with a tectiform and subacute top; the adventive lobe is As discussed previously, specimens, which we refer to this asymmetric with both flanks curved (Fig. 53E). species, have been frequently included in the stratigraphi- The suture line of paratype UMNH IP 4004 (Fig. 54D) cally older species G. crenistria and G. americanus. has, at 17 mm diameter, a V-shaped external lobe with al- G. americanus and the similar G. hudsoni possess narrower most non-curved flanks. Width/depth ratios of the external external lobes; G. crenistria is clearly separated by its al- lobe are: 0.35 at the base, 0.56 at half depth, and 0.93 at the most straight flanks of the sutural elements. Goniatites top. The ventrolateral saddle is slightly asymmetric and has eganensis is regarded by us as the most widespread mem- a subacute top. The adventive lobe is asymmetric with a ber of the genus in the lower 48 states region and a key ele- lesser curved ventral flank. The width ratio of external lobe ment for continental scale correlation. It can be recognized to adventive lobe is 1.00. in Nevada, Utah, Texas, Oklahoma, and Arkansas, and is

178 Dieter Korn & Alan L. Titus • Goniatites Zone (middle Mississippian) ammonoids, Nevada and Utah

A B

CD

Figure 55. Goniatites sowerbyi sp. nov. • A – holotype UMNH IP 4065 from bed 6 (sample 93NVLI-3) of Trough Springs Canyon; × 2.0. • B – paratype UMNH IP 4064 from bed 16 (sample 01UTMI-49) of Conger Mountain East; × 2.5.•C–paratype UMNH IP 4062 from bed 28 (sample 93UTMI-27) of Jensen Wash; × 2.5. • D – paratype UMNH IP 4066 from bed 6 (sample 93NVLI-3) of Trough Springs Canyon; × 2.5. the only unequivocal Brigantian species of Goniatites the to 1.00–1.15); decreasing in later ontogeny. Conch subevo- eastern and western United States have in common. In the lute in early ontogeny (uw/dm = 0.30–0.35 at 1–2.5 mm dia- east, it is typically the oldest species found where it is asso- meter) and involute in all stages larger than 8 mm diameter ciated with Girtyoceras welleri Gordon 1965. (uw/dm = 0.02–0.10). Aperture low in all stages (WER = 1.40–1.60). Ornament with crenulated growth-lines for- ming a low ventral projection. Suture line at 25 mm conch Goniatites sowerbyi sp. nov. diameter with narrow external lobe (0.55 of the external Figures 55–60 lobe depth; 1.05 of the ventrolateral saddle width), and mo- derately low median saddle (0.40 of the external lobe Derivation of name. – After James Sowerby (1757–1822), depth). External lobe V-shaped with very narrow, who wrote the first valid descriptions of Carboniferous am- V-shaped prongs; ventrolateral saddle narrowly rounded. monoids, including Goniatites sphaericus, the type species for the genus. Description. – The species shows some variability in the conch shape, but the ontogeny of all sectioned specimens is Holotype. – Specimen UMNH IP 4065, illustrated in very similar. The initial stage (at 1 mm dm) is thickly pa- Fig. 55A. chyconic and subevolute (ww/dm = 0.70; uw/dm = 0.35), and then there is a conspicuous widening of the conch to- Type locality and horizon. – Trough Springs Canyon, bed 6 wards a globular or spindle-shaped form in later ontogeny. (sample 93NVLI-3); Camp Canyon Member of Chainman The umbilicus is opened up to a conch diameter of 3 mm Formation, Goniatites eganensis Biozone. and thereafter becomes narrower, so that all stages larger than 8 mm are involute. Material. – 19 specimens; conch diameter up to 54 mm. The four sectioned paratypes (Fig. 57A–D) closely re- semble each other in their conch ontogeny, but two of them Diagnosis. – Goniatites with increasing conch thickness (specimens UMNH IP 4067 and UMNH IP 4068) are stouter between 1 and 5 mm diameter (ww/dm increasing from 0,70 than the specimens UMNH IP 4077 and UMNH IP 4063.

179 Bulletin of Geosciences • Vol. 86, 1, 2011

A B

Figure 56. Goniatites sowerbyi sp. nov. from bed 44 of Hamilton Canyon.•A–paratype MB.C.12032.1; × 1.0.•B–paratype MB.C.12032.2; × 1.5.

Table 34. Conch ontogeny (Fig. 57) of Goniatites sowerbyi sp. nov. dm conch shape whorl cross section shape aperture 1.5 mm thickly pachyconic; subevolute strongly depressed; strongly embracing low (WER = 1.55–1.65) (ww/dm = 0.75–0.85; uw/dm = 0.30–0.35) (ww/wh = 2.00–2.30; IZR = 0.40–0.45) 5 mm globular or spindle-shaped; involute strongly depressed; very strongly embracing very low or low (WER = 1.45–1.65) (ww/dm = 0.95–1.15; uw/dm = 0.10–0.20) (ww/wh = 2.00–2.50; IZR = 0.50–0.65) 10 mm globular or spindle-shaped; involute mod. or strongly depressed; very strongly embracing very low or low (WER = 1.45–1.65) (ww/dm = 0.95–1.15; uw/dm = 0.05–0.10) (ww/wh = 1.80–2.30; IZR = 0.50–0.65) 25 mm globular; involute moderately depressed; very strongly embracing very low or low (WER = 1.45–1.65) (ww/dm = 0.85–0.95; uw/dm = 0.05–0.08) (ww/wh = 1.60–1.75; IZR = 0.50–0.65) 50 mm globular; involute moderately depressed; very strongly embracing very low or low (WER = 1.45–1.65) (ww/dm = 0.85–0.95; uw/dm = 0.05–0.08) (ww/wh = 1.60–1.75; IZR = 0.50–0.65)

Table 35. Conch dimensions (in mm) and proportions for reference specimens of Goniatites sowerbyi sp. nov.

dm ww wh uw ah ww/dm ww/wh uw/dm WER IZR PT MB.C.12032.1 53.8 35.0 27.2 4.7 10.4 0.65 1.29 0.09 1.53 0.62 PT MB.C.12032.2 28.7 25.1 14.8 2.4 5.8 0.87 1.70 0.08 1.57 0.61 HT UMNH IP 4065 26.6 25.0 13.7 2.0 4.3 0.94 1.83 0.08 1.42 0.69 PT UMNH IP 4062 17.1 16.2 9.3 1.6 3.8 0.95 1.75 0.09 1.65 0.59 PT UMNH IP 4066 16.8 17.0 9.6 1.3 3.1 1.01 1.78 0.08 1.50 0.68 PT UMNH IP 4061 15.0 15.1 7.6 1.3 2.8 1.01 1.99 0.08 1.50 0.64 PT UMNH IP 4064 14.2 15.9 7.9 0.9 2.8 1.12 2.02 0.06 1.56 0.64

The holotype, UMNH IP 4065 (Fig. 55A), is a fully conch diameter (Fig. 58A). It is thinly pachyconic and in- septate specimen of 27 mm conch diameter that shows the volute (ww/dm = 0.65, uw/dm = 0.09) with a low aperture characteristic globular and involute morphology of the spe- (WER = 1.53). The suture line of this specimen shows a cies (ww/dm = 0.94; uw/dm = 0.08). It possesses a very V-shaped external lobe and a subacute ventrolateral saddle narrow aperture, and hence a low whorl expansion rate of (Fig. 58C). The median saddle reaches nearly half of the only 1.42. Parts of the shell ornament are preserved; there external lobe depth. are fine crenulated growth lines, which form a low The suture line of holotype UMNH IP 4065 shows, at dorsolateral projection, a shallow lateral sinus, and a low 26 mm conch diameter, a V-shaped external lobe with ventral projection. The internal mould shows shallow and rather strongly diverging, slightly sinuous flanks, a nar- wide constrictions, which extend parallel to the growth rowly rounded ventrolateral saddle, and an adventive lobe lines (Fig. 57G). with strongly curved flanks (Fig. 57G). The largest available specimen from Hamilton Canyon The suture lines of the two smaller paratypes is the fully septate paratype MB.C.12032.1 with 54 mm MB.C.12032.3 and UMNH IP 4061 (Fig. 57E, F), obtained

180 Dieter Korn & Alan L. Titus • Goniatites Zone (middle Mississippian) ammonoids, Nevada and Utah

H

I G

F J

E

D A BC

Figure 57. Goniatites sowerbyi sp.nov.•A–cross section of paratype UMNH IP 4063 from bed 28 (sample 93UTMI-27) of Jensen Wash; × 2.5. • B – cross section of paratype UMNH IP 4077 from bed 44 (sample 07NVWP-3) of Hamilton Canyon; × 2.5.•C–cross section of paratype UMNH IP 4067 from bed 6 (sample 93NVLI-3) of Trough Springs Canyon; × 2.5.•D–cross section of paratype UMNH IP 4068 from bed 6 (sample 93NVLI-3) of Trough Springs Canyon; × 2.5.•E–suture line of paratype MB.C.12032.3 from bed 44 of Hamilton Canyon, at 12.1 mm diameter, 11.2 mm ww, 6.2 mm wh;×4.0.•F–growth line course and suture line of paratype UMNH IP 4061 from bed 25 (sample 01UTMI-5) of South Burbank Hills, at 14.3 mm diam- eter, 14.4 mm ww, 7.6 mm wh; × 4.0.•G–suture line and constriction of holotype UMNH IP 4065 from bed 6 (sample 93NVLI-3) of Trough Springs Canyon, at 25.8 mm dm, 24.7 mm ww, 10.6 mm wh; × 4.0. • H–J – ontogenetic development of the conch width index (ww/dm), umbilical width index (uw/dm), and whorl expansion rate (WER) of all available specimens. at 11 and 14 mm conch diameter, differ from the holotype Various species of Goniatites have been shown to dis- as they have parallel-sided external lobes and broadly play wide intraspecific variability and possess more rounded ventrolateral saddles. discoidal and cuboid forms (Korn et al. 2004). It can be precluded that G. sowerbyi is a cuboid variant of G. ega- Discussion. – Goniatites sowerbyi sp. nov. differs from other nensis, because connecting forms appear to be completely North American species of the genus because of its globu- lacking and the sutural differences are profound. G. ega- lar or spindle-shaped conch combined with a rather long nensis possesses an acute ventrolateral saddle, while this is subevolute early juvenile stage. Variants of G. americanus narrowly rounded in G. sowerbyi. are also globular, but the inner whorls are not as widely G. sowerbyi sp. nov. closely resembles the holotype of G. umbilicate as in G. sowerbyi. sphaericus in conch shape, but the umbilicus is slightly wider

181 Bulletin of Geosciences • Vol. 86, 1, 2011

A B C

Figure 58. Goniatites sowerbyi sp. nov. from bed 44 of Hamilton Canyon.•A–dorsal view of paratype MB.C.12032.1; × 1.0.•B–dorsal view of paratype MB.C.12032.2; × 1.0. • C – suture line of paratype MB.C.12032.1, at 31.0 mm ww, 19.0 mm wh; × 3.0.

Table 36. Suture line proportions (Fig. 57) for Goniatites sowerbyi sp. nov. specimen at dm EL w/d EL/VLS EL/AL MS h VLS w/h remarks MB.C.12032.1 ca 40 0.50 1.21 1.08 0.49 0.41 VL saddle subacute UMNH IP 4065 25.8 0.54 1.05 0.88 0.41 0.52 E lobe V-shaped, flanks sinuous UMNH IP 4061 14.3 0.56 1.09 0.77 0.31 0.51 E lobe parallel-sided MB.C.12032.3 12.1 0.55 0.94 0.89 0.32 0.58 E lobe parallel-sided in G. sphaericus (uw/dm = 0.18 at 22 mm dm). Their suture 1934; Rotocanites Weyer, 1965 [synonym of Praedaraeli- lines are also different; G. sphaericus has an acute ventro- tes Schindewolf, 1934]. lateral saddle, which is narrowly rounded in the new species. There is also some resemblance to the unusual taxon Sygambrites wollbriggensis Korn, 1988, which has not been Genus Praedaraelites Schindewolf, 1934 reported again since its introduction and still is an enigmatic form. The latter has a very similar, but slightly wider Type species. – Daraelites culmiensis Kobold, 1933 (origi- umbilicate conch and also an ornament with crenulated, nal designation). ventrally projecting growth lines. The suture line of S. woll- briggensis, however, is rather dissimilar, as it has a Genus definition. – Epicanitinae with a suture line of which Y-shaped external lobe and a tectiform ventrolateral saddle. at least the adventive lobe is notched; other lobes are occa- sionally serrated.

Order Prolecanitida Miller & Furnish, 1954 Included species. – acutus: Praedaraelites (Praedaraeli- Suborder Prolecanitina Miller & Furnish, 1954 tes) acutus Ruan, 1981, p. 167; Guangxi; aktubensis: Prae- Superfamily Prolecanitaceae Hyatt, 1884 daraelites aktubensis Ruzhencev, 1949, p. 740; South Urals; apiculus: Praedaraelites (Praedaraelites) apiculus Included families. – Prolecanitidae Hyatt, 1884; Daraeliti- Ruan, 1981, p. 166; Guangxi; bowlandensis: Epicanites dae Tchernow, 1907. bowlandensis Moore, 1952, p. 73; Lancashire [synonym of P. culmiensis]; culmiensis: Daraelites culmiensis Kobold, Family Daraelitidae Tchernow, 1907 1933, p. 506; Harz; curtus: Praedaraelites (Rotocanites) curtus Ruan, 1981, p. 170; Guangxi; dangeardi: Epicanites Included subfamilies. – Epicanitinae Weyer, 1965; Darae- dangeardi Pareyn, 1961, p. 91; Western Algeria; densus: litinae Tchernow, 1907. Praedaraelites (Praedaraelites) densus Liang & Wang, 1991, p. 65; Xinjiang; inflatus: Praedaraelites (Rotocanites) Subfamily Epicanitinae Weyer, 1965 inflatus Liang & Wang, 1991, p. 69; Xinjiang; involutus: Prae- daraelites (Praedaraelites) involutus Ruan, 1981, p. 167; Included genera. – Epicanites Schindewolf, 1926; Libro- Guangxi; loeblichi: Epicanites loeblichi Miller & Furnish, vitchites Andrianov, 1985; Praedaraelites Schindewolf, 1940, p. 372; Oklahoma; longilobatus: Praedaraelites

182 Dieter Korn & Alan L. Titus • Goniatites Zone (middle Mississippian) ammonoids, Nevada and Utah

A B

Figure 59. Praedaraelites loeblichi (Miller & Furnish, 1940). • A – specimen UMNH IP 4096 from bed 44 (sample 07NVWP-3) of Hamilton Canyon; × 3.0. • B – specimen UMNH IP 4095 from bed 28 (sample 93UTMI-27) of Jensen Wash; × 4.0.

(Rotocanites) longilobatus Liang & Wang, 1991, p. 66; be treated as synonyms. The genus is widely distributed, but Xinjiang; medius: Praedaraelites (Praedaraelites) medius very rare in the western United States. It is restricted to dis- Liang & Wang, 1991, p. 65; Xinjiang; nandanensis: Prae- tinct stratigraphic horizons in North Africa, Iberia, daraelites (Rotocanites) nandanensis Ruan, 1981, p. 169; North-west and Central Europe, but stratigraphically more Guangxi; orientalis: Praedaraelites (Rotocanites) orienta- variable in the South Urals and North China. lis Ruan, 1981, p. 168; Guangxi; ovalis: Praedaraelites ovalis Sheng, 1983, p. 51; Tibet; postculmiensis: Praeda- ralites postculmiensis Kullmann, 1963, p. 352; Cantabrian Praedaraelites loeblichi (Miller & Furnish, 1940) Mountains [synonym of P. saharensis]; praecursor: Dara- Figures 59, 60 elites praecursor Fromaget, 1931, p. 659; Laos; pyrenai- cus: Daraelites praecursor pyrenaicus Delépine, 1935, 1940 Epicanites loeblichi Miller & Furnish, p. 372, pl. 48, p. 174; Pyrenees; quadratus: Praedaraelites (Praedaraeli- figs 13–16. tes) quadratus Ruan, 1981, p. 168; Guangxi; saharensis: Praedaraelites praecursor var. saharensis Pareyn, 1961, Holotype. – Specimen 1410 (State University Iowa), illus- p. 92; Western Algeria; simulans: Praedaralites simulans trated by Miller & Furnish (1940) on pl. 48, figs 14–16. Kullmann, 1963, p. 349; Cantabrian Mountains [synonym of P. dangeardi]; sobolevi: Epicanites sobolevi Kusina, Type locality and horizon. – South of Ada, Pontotoc Co., 1999, p. 47; Novaya Zemlya; viriosus: Praedaraelites Oklahoma; lower Caney Shale, Goniatites multiliratus (Praedaraelites) viriosus Ruan, 1981, p. 165; Guangxi; Biozone. xinjiangensis: Praedaraelites (Rotocanites) xinjiangensis Liang & Wang, 1991, p. 67; Xinjiang. Material. – 15 specimens; conch diameter up to 21 mm.

Discussion. – The relationships between the genera Epicani- Diagnosis. – Species of Praedaraelites with a combination tes Schindewolf, 1926 and Praedaraelites Schindewolf, of stronger denticulation of the adventive lobe and a less 1934 are not solved. The only difference between the two pouched, lower external lobe (width/depth ratio of external genera is the presence or absence of lobe serration, a charac- lobe is 0.67) than other species. ter that may be only of specific value. Both genera belong to the very slowly evolving daraelitids, possessing very similar Description. – The best-preserved specimen UMNH IP conch morphologies that allow only rarely the clear separa- 4096 from Hamilton Canyon. It has a diameter of 20.4 mm tion of species. In the following, the separation of the two and consists of a chambered internal mould with half a vo- genera is used tentatively because of the distinct septal infle- lution of body chamber also preserved (Fig. 59A). This xions causing the serration of the adventive lobe. specimen illustrates the transformation of the juvenile ser- More than twenty species of Praedaraelites have been penticonic conch with circular whorl cross section into the described so far (AMMON database; Korn & Ilg 2010), and thin discoidal, moderately umbilicate adult morphology fourteen of these from occurrences in China alone. Most of (ww/dm = 0.36; uw/dm = 0.27) with remarkable heighten- the species are not well characterised and some of these may ing of the aperture (WER increasing to a value of 2.80),

183 Bulletin of Geosciences • Vol. 86, 1, 2011

C

B

D

A

Figure 60. Praedaraelites loeblichi (Miller & Furnish, 1940). • A – suture line of specimen UMNH IP 4096 from bed 44 (sample 07NVWP-3) of Ham- ilton Canyon, at 4.4 mm ww, 5.1 mm wh; × 10.0.•B–suture line of specimen UMNH IP 4100 from bed 25 (sample 01UTMI-5) of South Burbank Hills, at 19.1 mm diameter, 6.9 mm ww, 8.8 mm wh; × 7.0. • C, D – ontogenetic development of the conch width index (ww/dm), umbilical width index (uw/dm), and whorl expansion rate (WER) of all available specimens.

Table 37. Conch dimensions (in mm) and proportions for reference specimens of Praedaraelites loeblichi (Miller & Furnish, 1940).

dm ww wh uw ah ww/dm ww/wh uw/dm WER IZR UMNH IP 4096 20.4 7.4 10.8 5.6 8.2 0.36 0.68 0.27 2.80 0.24 UMNH IP 4100 18.9 6.9 8.9 4.9 7.3 0.36 0.77 0.26 2.63 0.18 UMNH IP 4102 18.0 6.9 9.1 4.9 7.1 0.38 0.76 0.27 2.74 0.22 UMNH IP 4093 12.3 3.8 4.3 4.1 4.1 0.31 0.88 0.33 2.23 0.05 UMNH IP 4095 11.6 4.1 4.4 4.2 4.1 0.35 0.93 0.36 2.38 0.07 holotype 1410 9.0 3.1 3.3 3.6 3.1 0.34 0.94 0.40 2.33 0.06 flattened flanks, and an oblique umbilical wall. Only some The suture of specimen UMNH IP 4096 shows, in an patches of shell are preserved, they show very delicate earlier stage, similar elements (Fig. 60A). The external growth lines, which appear to be strongest on the umbilical lobe is more strongly pouched, and the adventive lobe wall. shows a denticulation on its ventral side. The adventive The suture line of specimen UMNH IP 4100 shows the lobe has a blunt base and lacks denticulation. characteristic criteria for the genus (Fig. 60B). The external lobe is slightly pouched in its lower half; its width is two Discussion. – The type material from the Caney Shale con- thirds of the lobe depth, and the width of the lower part is sists of small specimens, of which the largest (holotype 1410) 1.35 of the width in the upper half where the lobe flanks has a conch diameter of only 9 mm. At this stage, the denticu- converge. A narrow, pouched ventrolateral saddle follows lation of the lobes is not developed, as proven by the new ma- on the ventrolateral shoulder, which is in turn succeeded by terial. The holotype displays the immature morphology of the an adventive lobe that is the most prominent sutural ele- species with a rather wide umbilicus and a shell ornament ment, being 1.16 times wider than the external lobe and consisting of well-visible growth lines like the small speci- having an asymmetric, drop-shaped outline. It is distinctly mens newly collected from the Chainman Formation. serrated at its base, with the largest denticles in the centre. With so many previously named species of Praeda- These denticles are visible as delicate marginal inflexions raelites, several of which are not clearly defined, the valid- on the septum. An additional three lobes are present on the ity of the various species might be questioned. However, flank and umbilical wall; the outer of these is also P. loeblichi displays a very distinctive suture line, with a drop-shaped but narrow with a cragged base and the other unique combination of stronger denticulation of the two are rounded. These lobes are separated by rounded, adventive lobe with only incipient pouching of the shallow partly pouched saddles. Lobes and saddles have the same external lobe (in P. culmiensis, the width/depth ratio of the width in this area. external lobe is 0.85 in contrast to 0.67 in P. loeblichi).

184 Dieter Korn & Alan L. Titus • Goniatites Zone (middle Mississippian) ammonoids, Nevada and Utah

Acknowledgements CAMPBELL, K.S.W., BROWN, D.A. & COLEMAN, A.R. 1983. Ammonoids and the correlation of the lower Carboniferous We would like to thank Barry Richards (Calgary), Nick Riley rocks of eastern Australia. Alcheringa 7(2), 75–123. (Nottingham), Kevin Bylund (Provo) for assistance in the field. DOI 10.1080/03115518308619623 Technical support (photography, fossil preparation) was provided COLLINSON, C.W. 1955. Mississippian prolecanitid goniatites by Wolfgang Gerber (Tübingen), Evelin Stenzel, and David from Illinois and adjacent areas. Journal of Paleontology 29, Schmelzle (Berlin). Logistical support was provided by the U.S. 433–438. Bureau of Land Management (BLM). DK acknowledges finan- CONIL, R., GROESSENS, M.L., POTY,E.&TOURNEUR, F. 1990. Car- cial support by the German Research Foundation (Deutsche boniferous guide foraminifera, corals, and conodonts in the Forschungsgemeinschaft; project KO1829/6-1). We also thank Franco-Belgian and Campine basins: their potential for wide- the reviewers Kenneth de Baets and Christian Klug (Zurich) for spread correlation. Courier Forschungsinstitut Senckenberg their useful comments. 130, 15–30. COZAR, P., SOMERVILLE, I.D., ARETZ,M.&HERBIG, H.-G. 2005. Biostratigraphical dating of upper Viséan limestones (NW Ire- References land) using foraminiferans, calcareous algae and rugose cor- als. Irish Journal of Earth Sciences 23, 1–23. ANDRIANOV, V.N. 1985. Permskie i nekotorye kamennougolnye CURRIE, E.D. 1954. Scottish Carboniferous Goniatites. Transac- ammonoidei Severo-Vostoka Azii. Trudy Geologicheskogo tions of the Royal Society of Edinburgh 622(14), 527–602. Instituta (Novosibirsk), Izdatel’stvo Nauka Sibirskoye Otde- DELÉPINE, G. 1935. Contribution à l’étude de la faune du leniye, 1–180. Dinantien des Pyrénées. Deuxième partie: La faune de ARTHABER,G.VON 1911. Die Trias von Albanien. Beiträge zur Mondette. 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Die Goniatiten des Kulmplattenkalkes (Cephalo- (Montagne Noire, France), 57–85. In LANDMAN, N.H., DAVIS, poda, Ammonoidea; Unterkarbon; Rheinisches Schieferge- R.A. & MAPES, R.H. (eds) Cephalopods Present and Past: birge). Geologie und Paläontologie in Westfalen 11, 1–293. New Insights and Fresh Perspectives. Springer, New York. KORN, D. 1990. Weitere Goniatiten aus dem Ober-Visé des DOI 10.1007/978-1-4020-6806-5_3 Sauerlandes (Cephalopoda, Ammonoidea; Unterkarbon; KORN, D., KLUG,C.&MAPES, R.H. 1999. Viséan and Early Rheinisches Schiefergebirge). Geologie und Paläontologie in Namurian Ammonoids from the Tafilalt (Eastern Anti-Atlas, Westfalen 15, 11–69. Morocco). Abhandlungen der Geologischen Bundesanstalt KORN, D. 1993. Stratigraphie und Fossilführung der Visé/Na- 54, 345–375. mur-Aufschlüsse am Bau der A46 bei Arnsberg/Westfalen. KORN, D., KLUG,C.&MAPES, R.H. 2004. Cuboid Carboniferous Geologie und Paläontologie in Westfalen 23, 35–60. ammonoids. 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Palaeontologia Sinica, Series B 180, 1–171. development in the British Carboniferous. Proceedings of the LIBROVITCH, L.S. 1957. O nekotorykh novykh gruppakh gonia- Yorkshire Geological Society 24(2), 103–128. titov iz kamennougolnykh otlozheniy SSSR. Ezhegodnik Vse- DOI 10.1144/pygs.24.2.103 soyuznogo Paleontologicheskogo Obshchestva 16, 246–272. MOORE, E.W.J. 1946. The Carboniferous Goniatite Genera MANGER, W.L. 1988. Phylogeny of the Carboniferous Ammonoid Girtyoceras and Eumorphoceras. Proceedings of the York- Family Dimorphoceratidae, 29–42. In WIEDMANN,J.&KULL- shire Geological Society 25, 387–445. MANN, J. (eds) Cephalopods – Present and Past. Schweizer- DOI 10.1144/pygs.25.6.387 bart, Stuttgart. MOORE, E.W.J. 1952. Notes on the genera Prolecanites and MANGER, W.L. & PAREYN, C. 1979. New Carboniferous dimor- Epicanites with description of two new species. Liverpool and phoceratid ammonoids from Algeria and Arkansas. Journal of Manchester Geological Journal 1(1), 71–76. Paleontology 53(3), 657–665. MOORE, E.W.J. 1958. Dimorphoceratidae from the Upper Viséan MANGER,W.L.&QUINN, J.H. 1972. Carboniferous dimorpho- shales of County Leitrim, Eire. Proceedings of the Yorkshire ceratid ammonoids from northern Arkansas. Journal of Pale- Geological Society 31(3), 219–226. ontology 46, 303–314. DOI 10.1144/pygs.31.3.219 MAPLES,C.G.&WATERS, J.A. 1987. Redefinition of the Mera- MORGAN, G.D. 1924. Geology of the Stonewall quadrangle, Okla- mecian/Chesterian boundary (Mississippian). Geology 15(7), homa. Bureau of Geology Bulletin 2, 185–186. 647–651. MULL, C.G., TAILLEUR, I.L., MAYFIELD, C.F., ELLERSIEK,I.& DOI 10.1130/0091-7613(1987)15<647:ROTMBM>2.0.CO;2 CURTIS, S.M. 1982. New upper Paleozoic and lower Mesozoic MARTIN, W. 1809. Petrificata Derbiensia; or, Figures and De- stratigraphic units, central and western Brooks Range, Alaska. scriptions of Petrifactions collected in Derbyshire.28pp. Bulletin of the American Association of Petroleum Geologists D. Lyon, Wigan. 1982, 348–362. MCCALEB, J.A., QUINN,J.H.&FURNISH, W.M. 1964. The am- MÜNSTER,G.GRAF ZU 1832. Ueber die Planuliten und Goniatiten monoid family Girtyoceratidae in the Southern Midcontinent. im Uebergangs-Kalk des Fichtelgebirges. 38 pp. Birner, Bay- Circular of the Oklahoma Geological Survey 67, 1–41. reuth. MEISCHNER,D.&NEMYROVSKA, T. 1999. Origin of Gnathodus NICOLAUS, H.-J. 1963. Zur Stratigraphie und Fauna der creni- bilineatus (Roundy, 1926) related to goniatite zonation in stria-Zone im Kulm des Rheinischen Schiefergebirges. Rheinisches Schiefergebirge, Germany. Bollettino della Beihefte zum Geologischen Jahrbuch 53, 1–246. Società Paleontologica Italiana 37(2–3), 427–442. OLIVEIRA,J.T.&WAGNER-GENTIS, C.H.T. 1983. The Mértola and MILLER, A.K. & FURNISH, W.M. 1940. Studies on Carboniferous Mira formation boundary between Dogueno and Almada de ammonoids: parts 1–4. Journal of Paleontology 14, 356–377. Ouro, marine Carboniferous of South Portugal, 1–39. In

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LEMOS DE SOUSA, M.J. (ed.) Contributions to the Carbonifer- RUZHENCEV, V.E. 1947. Predstabiteli semeystva Dimorpho- ous Geology and Palaeontology of the Iberian Peninsula. 259 ceratidae Hyatt v kamennougolnykh otlozheniyakh Urala. pp. Universidade do Porto, Porto. Doklady Akademiya Nauk SSSR 56(5), 521–524. PADGET, P. 1952. A new species of Beyrichoceras from the RUZHENCEV, V.E. 1949. Sistematika i evolyutsia semeystv Prono- “Yoredale beds”, County Tyrone, Northern Ireland. The an- ritidae Frech i Medlicottiidae Karpinsky. Trudy Paleonto- nals and magazine of natural history, zoology, botany and ge- logicheskogo Instituta Akademiya Nauk SSSR 19, 1–206. ology, new series 12(5), 864–868. RUZHENCEV, V.E. 1957. Filogeneticheskaya sistema paleo- PAREYN, C. 1961. Les Massifs Carbonifères du Sahara Sud- zoiskikh ammonoidei. Byulleten’ Moskovskogo Obshchestva Oranais. Tome II. Paléontologie stratigraphique. 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The Mountain Limestone District.XX+ RUZHENCEV, V.E. & BOGOSLOVSKAYA, M.F. 1969. Reviziya se- 259 pp. John Murray, London. meystva Dimorphoceratidae. Paleontologicheskiy Zhurnal PLUMMER, F.B. & SCOTT, G. 1937. Upper Paleozoic ammonites in 1969(1), 51–66. Texas. The geology of Texas, Bulletin of the Texas University RUZHENCEV,V.E.&BOGOSLOVSKAYA, M.F. 1970. Reviziya nad- 3701, 1–516. semeystva Goniatitaceae. Paleontologicheskiy Zhurnal POOLE, F.G. & SANDBERG, C.A. 1991. Mississippian paleogeo- 1970(4), 52–65. graphy and conodont biostratigraphy of the western United RUZHENCEV, V.E. & BOGOSLOVSKAYA, M.F. 1971. Namyurskiy States, 107–136. In COOPER,J.D.&STEVENS, C.H. (eds) Pa- etap v evolyutsii ammonoidey. Rannenamyurskie ammon- leozoic paleogeography of the western United States-II: Pa- oidei. Trudy Paleontologicheskogo Instituta Akademiya Nauk cific Section of the Society of Economic Paleontologists and SSSR 133, 1–382. Mineralogists 67. SADLICK, W.L. 1960. Some preliminary aspects of Chainman stra- POPOV, A.V. 1968. Vizeyskie ammonoidei cevernogo Tyan- tigraphy, 81–90. In BOETCHER,J.W.&SLOAN, W.W. JR. (eds) Shanya i ikh stratigraficheskoe zhachenie. Trudy Geologi- Guidebook to the geology of east-central Nevada: Inter- cheskiy Instituta, Kirgizskiy Filial Akademiya Nauk SSSR, mountain Association of Petroleum Geologists, 11th Annual 1–116. Field Conference. POTY,E.&HANCE, L. 2006. Warnantian. Geologica Belgica 9, SADLICK, W.L. 1965. Biostratigraphy of the Chainman Forma- 139–144. tion (Carboniferous), eastern Nevada and western Utah. RAMSBOTTOM, W.H.C. 1970. Some British Carboniferous gonia- 237 pp. Ph.D. dissertation, Salt Lake City, University of tites of the family Anthracoceratidae. Bulletin of the Geologi- Utah. cal Survey of Great Britain 32, 53–60. SADLICK, W.L. 1995. Stratigraphic subdivision of the Chainman RAMSBOTTOM, W.H.C. & SAUNDERS, W.B. 1985. Evolution and Formation, 3–27. In HANSEN, M.W., WALKER,J.P.&TREXLER, evolutionary biostratigraphy of Carboniferous ammonoids. J.H. JR. (eds) Mississippian source rocks in the Antler Basin of Journal of Paleontology 59, 123–139. Nevada and associated structural and stratigraphic traps. REPETSKI, J.E. & STAMM, R. 2009. Mississippian conodonts of the Fieldtrip Guidebook. Nevada Petroleum Society, Inc., Reno, Appalachian Basin, 59–61. In GREB, S.F. & CHESNUT, D.R. Nevada. (eds) Carboniferous of the Appalachian and Black Warrior SANDBERG, C.A., MORROW, J.R. & POOLE, F.G. 2008. New Mera- Basins. Kentucky Geological Survey, Special Publication 10. mecian unit on Mississippian Granite Mountain Island, Mid- RILEY, N.J. 1993. Dinantian (Lower Carboniferous) biostrati- dle Range, west-central Utah. Geological Society of America, graphy and chronostratigraphy in the British Isles. Journal of Joint Rocky Mountain and Cordilleran Sections Annual Meet- the Geological Society, London 150, 427–446. ing Abstracts with Programs, 41. DOI 10.1144/gsjgs.150.3.0427 SANDBERG, C.A., POOLE, F.G. & GUTSCHICK, R.C. 1980. Devonian RILEY, N.J. 1996. Mid-Dinantian ammonoids from the Craven and Mississippian stratigraphy and conodont zonation of Pilot Basin, northwest England. Special Papers in Palaeontology and Chainman Shales, Confusion Range, Utah, 71–79. In 53, 1–87. FOUCH,T.D.&MAGATHAN, E.R. (eds) Paleozoic paleo- ROEMER, F.A. 1850. Beiträge zur geologischen Kenntnis des geography of the west-central United States. Rocky Mountain nordwestlichen Harzgebirges. Palaeontographica 3, 1–69. Paleogeography Symposium I. Rocky Mountain Section, So- ROEMER, F.A. 1855. Beiträge zur geologischen Kenntniss des ciety of Economic Paleontologists and Mineralogists, Denver, nordwestlichen Harzgebirges. Zweite Abtheilung. Palaeon- Colorado. tographica 3, 69–111. SAUNDERS, W.B. 1966. New Goniatite Ammonoid from the Late RUAN YI-PING 1981. Carboniferous Ammonoid faunas from Qixu Mississippian of Arkansas. 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Mississippian and lower and middle Pennsylvanian ammon- in their study. Paleontologicheskogo Instituta Rossiyskaya oid biostratigraphy of Northern Arkansas. Oklahoma Geologi- Akademiya Nauk, Moskva. cal Survey Guidebook 18, 117–137. TITUS, A.L. 2000. Late Mississippian (Arnsbergian Stage-E2 SCHINDEWOLF, O.H. 1926. Beiträge zur Kenntnis der Cephalo- chronozone) ammonoid paleontology and biostratigraphy of podenfauna des oberfränkisch-ostthüringischen Unterkar- the Antler foreland basin, California. Bulletin of the Utah Geo- bons. Senckenbergiana 8, 63–96. logical Survey 131, 1–108. SCHINDEWOLF, O.H. 1934. Über zwei jungpaläozoische Cephalo- TITUS, A.L. & MANGER, W.M. 2001. Mid-carboniferous am- podenfaunen von Menorca. Abhandlungen der Gesellschaft monoid biostratigraphy, southern Nye County, Nevada: Impli- der Wissenschaften in Göttingen, Mathematisch-Physika- cations of the first North American Homoceras. Journal of Pa- lische Klasse III 10, 159–191. leontology, Supplement 4, 55, 1–31. SCHINDEWOLF, O.H. 1951. Über ein neues Vorkommen unter- DOI 10.1666/0022-3360(2001)75[1:MABSNC]2.0.CO;2 karbonischer Pericyclus-Schichten im Oberharz. Neues Jahr- TREXLER, J.H. JR., SNYDER, W., SCHWARZ, D., KURKA, M.T. & buch für Geologie und Paläontologie, Abhandlungen 93(1), CROSBY, R. 1995. An overview of the Mississippian Chainman 23–116. Shale. In HANSEN, M.W., WALKER,J.P.&TREXLER, J.H. (eds) SCHMIDT, H. 1925. Die carbonischen Goniatiten Deutschlands. Mississippian Source Rocks in the Antler Basin of Nevada and Jahrbuch der Preußischen Geologischen Landesanstalt 45 Associated Structural and Stratigraphic Traps. Fieldtrip (for 1924), 489–609. Guidebook. 165 pp. Nevada Petroleum Society, Reno, Ne- SCHMIDT, H. 1934. Cephalopodenfaunen des älteren Namur aus vada. der Umgegend von Arnsberg in Westfalen. Jahrbuch der TSCHANZ, C.M. & PAMPEYAN, E.H. 1970. Geology and mineral Preußischen Geologischen Landesanstalt 54 (for 1933), deposits of Lincoln County, Nevada. Nevada Bureau of Mines 440–461. and Geology Bulletin 73, 1–188. SCHMIDT, H. 1941. Eine neue Fauna mit Pericyclus von Riefens- TYNAN, M.C. 1980. Conodont biostratigraphy of the Mississip- beek im Harz. Jahrbuch der Reichsstelle für Bodenforschung pian Chainman Formation, western Millard County, Utah. 60 (for 1939), 148–156. Journal of Paleontology 54, 1282–1309. SELLERS, D.H.A. & FURNISH, W.M. 1960. Mississippian ammon- WANG MING-QIAN 1983. Cephalopoda, 514–533. In REGIONAL oids from northwestern Canada. Journal of Paleontology 34, GEOLOGICAL SURVEYING TEAM OF XINJIANG &XINJIANG GEO- 1124–1128. LOGICAL BUREAU et al. (eds) Fossil Atlas of Northwest China, SHENG HUAIBIN 1983. The ammonoids of late Lower Carbonifer- Xinjiang 2. Geological Publishing House, Beijing. ous from Yongzhu village, Xainza district in North Xizang. WEBSTER, G.D., GORDON,M.JR., LANGENHEIM, R.L. JR.&HENRY, The Geology of the Qinghai-Xizang (Tibet) Plateau, Beijing, T.W. 1984. Road logs for the Mississippian-Pennsylvanian 41–68. boundary in the eastern Great Basin; Salt Lake City, Utah, to SHUMARD, B.F. 1863. Descriptions of new Paleozoic fossils. Las Vegas, Nevada, Field trip 1, 1–86. In LINTZ,J.JR. (ed.) Transactions of the St. Louis Academy of Science 2, 108–113. Western geologic excursions, volume 1. Department of Geo- SILBERLING, N.J., NICHOLS, K.M., MACKE, D.L. & TRAPPE, J. 1995. logical Sciences, University of Nevada at Reno. Upper Devonian-Mississippian stratigraphic sequences in the WEDEKIND, R. 1918. Die Genera der Palaeoammonoidea Gonia- distal Antler foreland of western Utah and adjoining Nevada. titen). Mit Ausschluß der Mimoceratidae, Glyphioceratidae United States Geological Survey Bulletin 1988-H, 1–33. und Prolecanitidae. Paläontographica 62, 85–184. SKOMPSKI, S., PASZKOWSKI, M., KROBICKI, M., KOKOVIN, K., WEYER, D. 1965. Zur Ammonoideen-Fauna der Gattendorfia- KORN, D., TOMAS,A.&WRZOLEK, T. 2001. Depositional set- Stufe von Dzikowiec (Ebersdorf) in Dolny Slask (Nieder- ting of the Devonian/Carboniferous biohermal Boľshaya schlesien). Berichte der geologischen Gesellschaft der DDR Nadota Carbonate Complex, Subpolar Urals. Acta Geologica 10(4), 443–464. Polonica 51, 217–235. WEYER, D. 1972. Trilobiten und Ammonoideen aus der Ento- SMITH, J.P. 1897. The development of Glyphioceras and the phy- gonites nasutus-Zone (Unterkarbon) des Büchenberg-Sattels logeny of the Glyphioceratidae. Proceedings of the California (Elbingeröder Komplex, Harz). Teil I. Geologie 21(2), Acadademy of Science, Geology 1(3), 105–122. 166–184. SMITH, J.P. 1903. The Carboniferous Ammonoids of America. WORK, D.M., NASSICHUK, W.W. & RICHARDS, B.C. 2000. Lower Monographs of the United States Geological Survey 42, 1–211. Viséan ammonoids from the lower Mount Head Formation, SOWERBY, J. 1812–1814. The mineral conchology of Great Brit- east-central British Columbia. Geological Survey of Canada ain; or coloured figures and descriptions of those remains of Bulletin 541, 1–17. testaceous animals or shells, which have been preserved at WORTHEN, A.H. 1890. Description of fossil invertebrates. Geo- various times and depths in the earth. Vol. I. 234 pp. London. logical Survey of Illinois 8, 148–150. TCHERNOW, A.A. 1907. Artinskian Stage. I. Ammonoids from the YANG FENGQING 1986. Late Early Carboniferous ammonoids basins of Yayvy, Kos’vy, and Chusovoy. 1. Introduction. Re- from Chenmazijing of Zhongning, Ningxia. Acta Palaeon- view of investigated area. Prolecanitidae. Byulleten’ Mos- tologica Sinica 25(3), 260–271. kovskogo Obshchestva Ispytateley Prirody, Otdel Geologi- YOUNGQUIST, W. 1949a. The cephalopod fauna of the White Pine cheskiy 20(34), 270–401. Shale of Nevada. Journal of Paleontology 23, 276–305. TITUS, A.L. 1999. Ammonoid biostratigraphy of the Barnett Shale YOUNGQUIST, W. 1949b. The cephalopod fauna of the White Pine (late Mississippian), Texas, USA, 155–168. In ROZANOV, A.Y. Shale of Nevada: Supplement. Journal of Paleontology 23, &SHEVYREV, A.A. (eds) Fossil cephalopods: Recent advances 613–616.

190 Dieter Korn & Alan L. Titus • Goniatites Zone (middle Mississippian) ammonoids, Nevada and Utah

Appendix – Material used for the description of the ammonoid fauna (additional, in the stratigraphic columns mentioned but not catalogued material available)

Material in the Utah Museum of Natural History (Titus coll.):

Duckwater Hills; bed 4 (sample 93NVNY-1) Goniatites deceptus sp. nov. 23 specimens (UMNH IP 3845–3867)

Hamilton Canyon; bed 44 (sample 95NVWP-16) Girtyoceras hamiltonense sp. nov. 3 specimens (UMNH IP 3188–3190)

Hamilton Canyon; bed 44 (sample 07NVWP-3) Girtyoceras hamiltonense sp. nov. 23 specimens (UMNH IP 3127–3149) Metadimorphoceras richardsi sp. nov. 2 specimens (UMNH IP 3290–3291) Goniatites eganensis sp. nov. 10 specimens (UMNH IP 4010–4019) Goniatites sowerbyi sp. nov. 1 specimen (UMNH IP 4077) Praedaraelites loeblichi (Miller & Furnish, 1940) 4 specimens (UMNH IP 4096–4099)

Hamilton Canyon; bed 44 (sample 95NVWP-15) Girtyoceras hamiltonense sp. nov. 9 specimens (UMNH IP 3179–3187) Metadimorphoceras richardsi sp. nov. 1 specimen (UMNH IP 3293)

Trough Springs Canyon; bed 6 (sample 93NVLI-3) Goniatites eganensis sp. nov. 41 specimens (UMNH IP 4020–4061) Goniatites sowerbyi sp. nov. 12 specimens (UMNH IP 4065–4076)

Granite Mountain South; bed 17 (sample 94UTJU-1) Entogonites sp. 2 specimens (UMNH IP 2680–2681) Calygirtyoceras confusionense sp. nov. 15 specimens (UMNH IP 2692–2706) Calygirtyoceras arcticum (Gordon, 1957) 10 specimens (UMNH IP 2751–2760) Dimorphoceras rileyi sp. nov. 7 specimens (UMNH IP 3245–3246–3248–3252) Kazakhoceras bylundi sp. nov. 2 specimens (UMNH IP 3305–3311) Goniatites americanus Gordon, 1971 30 specimens (UMNH IP 3547–3575–3753) Praedaraelites loeblichi (Miller & Furnish, 1940) 1 specimen (UMNH IP 4093)

Granite Mountain South; bed 17 (sample 07UTJU-1) Bollandoceras occidentale sp. nov. 1 specimen (UMNH IP 2635) Entogonites sp. 1 specimen (UMNH IP 2679) Calygirtyoceras arcticum (Gordon, 1957) 4 specimens (UMNH IP 2779–2782) Dimorphoceras rileyi sp. nov. 8 specimens (UMNH IP 3253–3260) Kazakhoceras bylundi sp. nov. 1 specimen (UMNH IP 3306) Goniatites americanus Gordon, 1971 9 specimens (UMNH IP 3450–3458)

Granite Mountain South; bed 22 (sample 94UTJU-2) Goniatites americanus Gordon, 1971 32 specimens (UMNH IP 3488–3519)

Granite Mountain South; bed 25 (sample 94UTJU-4) Entogonites acus sp. nov. 2 specimens (UMNH IP 2660–2661) Calygirtyoceras arcticum (Gordon, 1957) 18 specimens (UMNH IP 2761–2778) Girtyoceras primum sp. nov. 70 specimens (UMNH IP 2977–3046) Dimorphoceras rileyi sp. nov. 1 specimen (UMNH IP 3247) Dimorphoceratidae sp. indet. 1 specimen (UMNH IP 3267) Goniatites americanus Gordon, 1971 127 specimens (UMNH IP 3576–3702) Praedaraelites loeblichi (Miller & Furnish, 1940) 1 specimen (UMNH IP 4094)

Granite Mountain South; bed 25 (sample 05UTJU-12) Entogonites acus sp. nov. 1 specimen (UMNH IP 2655) Calygirtyoceras arcticum (Gordon, 1957) 5 specimens (UMNH IP 2718–2722)

191 Bulletin of Geosciences • Vol. 86, 1, 2011

Girtyoceras primum sp. nov. 9 specimens (UMNH IP 2951–2959) Girtyoceras primum sp. nov. 3 specimens (UMNH IP 3090–3092) Dimorphoceras rileyi sp. nov. 1 specimen (UMNH IP 3240) Goniatites americanus Gordon, 1971 34 specimens (UMNH IP 3392–3418–3520–3525–3800)

Granite Mountain South; bed 25 (sample 04UTJU-3) Goniatites americanus Gordon, 1971 2 specimens (UMNH IP 3290–3291)

Granite Mountain South; bed 33 (sample 94UTJU-3b) Goniatites deceptus sp. nov. 2 specimens (UMNH IP 3965–3966)

Granite Mountain North; bed 25 (sample 94UTJU-9) Entogonites acus sp. nov. 2 specimens (UMNH IP 2656–2657) Calygirtyoceras arcticum (Gordon, 1957) 13 specimens (UMNH IP 2723–2739–2750) Girtyoceras primum sp. nov. 43 specimens (UMNH IP 3047–3089) Dimorphoceras rileyi sp. nov. 3 specimens (UMNH IP 3230–3243–3244) Goniatites americanus Gordon, 1971 60 specimens (UMNH IP 3703–3752–3754–3763)

Granite Mountain North; bed 33 (sample 97UTJU-4) Goniatites deceptus sp. nov. 11 specimens (UMNH IP 3818–3823–3960–3965)

Granite Mountain North; bed 33 (sample 05UTJU-13) Goniatites deceptus sp. nov. 7 specimens (UMNH IP 3830–3832–3968–3972)

Granite Mountain North; bed 35 (sample 94UTJU-10) Goniatites deceptus sp. nov. 67 specimens (UMNH IP 3816–3817–3868–3932)

Granite Mountain North; bed 35 (sample 05UTJU-14) Goniatites deceptus sp. nov. 1 specimen (UMNH IP 3833)

Middle Confusion Range 1; bed 6 (sample 07UTMI-3) Dimorphoceratidae sp. indet. 1 specimen (UMNH IP 3265) Goniatites americanus Gordon, 1971 2 specimens (UMNH IP 3359–3360)

Middle Confusion Range 1; bed 10 (sample 05UTMI-3) Bollandoceras occidentale sp. nov. 5 specimens (UMNH IP 2630–2634) Kazakhoceras bylundi sp. nov. 2 specimens (UMNH IP 3309–3310) Goniatites americanus Gordon, 1971 5 specimens (UMNH IP 3434–3438)

Middle Confusion Range 1; bed 10 (sample 07UTMI-4) Goniatites americanus Gordon, 1971 6 specimens (UMNH IP 3361–3366)

Middle Confusion Range 1; bed 12 (sample 05UTMI-5) Dimorphoceratidae sp. indet. 1 specimen (UMNH IP 3264) Goniatites americanus Gordon, 1971 5 specimens (UMNH IP 3445–3449)

Middle Confusion Range 2; bed 11 (sample 05UTMI-9) Bollandoceras sp. 1 specimen (UMNH IP 2636) Goniatites americanus Gordon, 1971 5 specimens (UMNH IP 3441–3444)

Middle Confusion Range 2; bed 14 (sample 05UTMI-7) Goniatites americanus Gordon, 1971 2 specimens (UMNH IP 3439–3240)

Middle Confusion Range 2; bed 15 (sample 07UTMI-6) Dimorphoceratidae sp. indet. 1 specimen (UMNH IP 3266)

Middle Confusion Range 3; bed 10 (sample 05UTMI-10) Dimorphoceratidae sp. indet. 2 specimens (UMNH IP 3270–3271) Goniatites americanus Gordon, 1971 15 specimens (UMNH IP 3419–3433)

192 Dieter Korn & Alan L. Titus • Goniatites Zone (middle Mississippian) ammonoids, Nevada and Utah

Conger Mountain West; bed 19 (sample 01UTMI-42) Dimorphoceratidae sp. indet. 1 specimen (UMNH IP 3263) Goniatites deceptus sp. nov. 7 specimens (UMNH IP 3834–3837–3993–3995)

Conger Mountain West; bed 19 (sample 01UTMI-43) Goniatites deceptus sp. nov. 15 specimens (UMNH IP 3945–3959)

Conger Mountain West; bed 21 (sample 01UTMI-40) Dimorphoceratidae sp. indet. 1 specimen (UMNH IP 3262) Goniatites deceptus sp. nov. 13 specimens (UMNH IP 3972–3984)

Conger Mountain East; bed 14 (sample 01UTMI-48) Dimorphoceratidae sp. indet. 1 specimen (UMNH IP 3261) Goniatites americanus Gordon, 1971 12 specimens (UMNH IP 3786–3797)

Conger Mountain East; bed 16 (sample 01UTMI-49) Goniatites deceptus sp. nov. 13 specimens (UMNH IP 3985–3992) Goniatites sowerbyi sp. nov. 1 specimen (UMNH IP 4064)

Needle Range 1; bed 16 (sample 00UTMI-1n) Girtyoceras primum sp. nov. 30 specimens (UMNH IP 2834–2863) Dimorphoceratidae sp. indet. 1 specimen (UMNH IP 3268) Goniatites americanus Gordon, 1971 1 specimen (UMNH IP 3312)

Needle Range 1; bed 18, 19 (sample 00UTMI-6n) Dimorphoceratidae sp. indet. 1 specimen (UMNH IP 3269) Goniatites americanus Gordon, 1971 3 specimens (UMNH IP 3313–3315)

Needle Range 1; single bullion (sample 07UTMI-10) Entogonites acus sp. nov. 2 specimens (UMNH IP 2658–2659) Goniatites americanus Gordon, 1971 22 specimens (UMNH IP 3764–3785)

South Burbank Hills; bed 5 (sample 01UTMI-2) Entogonites burbankensis sp. nov. 4 specimens (UMNH IP 2637–2640) Entogonites sp. 1 specimen (UMNH IP 2678) Dimorphoceras worki sp. nov. 1 specimen (UMNH IP 3229) Metadimorphoceras mangeri sp. nov. 6 specimens (UMNH IP 3278–3283) Goniatites americanus Gordon, 1971 26 specimens (UMNH IP 3316–3351)

South Burbank Hills; bed 6 (sample 01UTMI-3) Calygirtyoceras arcticum (Gordon, 1957) 5 specimens (UMNH IP 2728–2737) Girtyoceras primum sp. nov. 87 specimens (UMNH IP 2864–2950) Metadimorphoceras mangeri sp. nov. 5 specimens (UMNH IP 3273–3277) Goniatites americanus Gordon, 1971 20 specimens (UMNH IP 3352–3371)

South Burbank Hills; bed 8 (sample 07UTMI-6) Entogonites acus sp. nov. 1 specimen (UMNH IP 2662) Calygirtyoceras arcticum (Gordon, 1957) 12 specimens (UMNH IP 2783–2794) Girtyoceras primum sp. nov. 13 specimens (UMNH IP 2960–2972)

South Burbank Hills; bed 14 (sample 01UTMI-4) Girtyoceras gordoni sp. nov. 8 specimens (UMNH IP 3093–3100) Dimorphoceras rileyi sp. nov. 4 specimens (UMNH IP 3233–3279–3239) Goniatites americanus Gordon, 1971 18 specimens (UMNH IP 3372–3389)

South Burbank Hills; bed 15 (sample 07UTMI-8) Goniatites americanus Gordon, 1971 6 specimens (UMNH IP 3467–3472)

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South Burbank Hills; bed 24 (sample 07UTMI-2) Girtyoceras gordoni sp. nov. 4 specimens (UMNH IP 3116–3119) Dimorphoceras rileyi sp. nov. 1 specimen (UMNH IP 3230)

South Burbank Hills; bed 26 (sample 07UTMI-1) Girtyoceras hamiltonense sp. nov. 29 specimens (UMNH IP 3150–3178) Girtyoceras sp. 1 specimen (UMNH IP 3200) Metadimorphoceras richardsi sp. nov. 1 specimen (UMNH IP 3292) Goniatites eganensis sp. nov. 6 specimens (UMNH IP 3997–4002)

South Burbank Hills; bed 26 (sample 01UTMI-5) Girtyoceras hamiltonense sp. nov. 16 specimens (UMNH IP 3120–3126–3191–3199) Metadimorphoceras richardsi sp. nov. 1 specimen (UMNH IP 3294) Goniatites eganensis sp. nov. 6 specimens (UMNH IP 4003–4009) Goniatites sowerbyi sp. nov. 1 specimen (UMNH IP 4061) Praedaraelites loeblichi (Miller & Furnish, 1940) 2 specimens (UMNH IP 4100–4101)

Jensen Wash; bed 7 (sample 93UTMI-25) Entogonites borealis Gordon, 1957 11 specimens (UMNH IP 2643–2653) Entogonites sp. 14 specimens (UMNH IP 2663–2676) Calygirtyoceras confusionense sp. nov. 14 specimens (UMNH IP 2688–2690–2707–2717) Calygirtyoceras arcticum (Gordon, 1957) 22 specimens (UMNH IP 2724–2727–2738–2795–2811) Calygirtyoceras sp. 22 specimens (UMNH IP 2812–2833) Dimorphoceras rileyi sp. nov. 2 specimens (UMNH IP 3231–3232) Metadimorphoceras mangeri sp. nov. 6 specimens (UMNH IP 3284–3289) Metadimorphoceras sp. 10 specimens (UMNH IP 3295–3304) Goniatites americanus Gordon, 1971 28 specimens (UMNH IP 3475–3487–3801–3815)

Jensen Wash; bed 7 (sample 97UTMI-9) Entogonites borealis Gordon, 1957 1 specimen (UMNH IP 2641) Calygirtyoceras confusionense sp. nov. 7 specimens (UMNH IP 2682–2687–2691) Dimorphoceras rileyi sp. nov. 2 specimens (UMNH IP 3241–3242) Kazakhoceras bylundi sp. nov. 1 specimen (UMNH IP 3307) Goniatites americanus Gordon, 1971 17 specimens (UMNH IP 3473–3474–3532–3546)

Jensen Wash; bed 9 (sample 97UTMI-10) Entogonites borealis Gordon, 1957 1 specimen (UMNH IP 2642) Entogonites sp. 1 specimen (UMNH IP 2677) Dimorphoceratidae sp. indet. 1 specimen (UMNH IP 3272) Goniatites americanus Gordon, 1971 2 specimens (UMNH IP 3798–3799)

Jensen Wash; bed 13 (sample 97UTMI-12) Entogonites acus sp. nov. 1 specimen (UMNH IP 2654) Girtyoceras primum sp. nov. 4 specimens (UMNH IP 2973–2976) Goniatites americanus Gordon, 1971 6 specimens (UMNH IP 3526–3531)

Jensen Wash; bed 19 (sample 97UTMI-13) Girtyoceras gordoni sp. nov. 15 specimens (UMNH IP 3101–3115) Dimorphoceras rileyi sp. nov. 3 specimens (UMNH IP 3234–3236) Kazakhoceras bylundi sp. nov. 1 specimen (UMNH IP 3308)

Jensen Wash; bed 26 (sample 97UTMI-14) Goniatites sp. 5 specimens (UMNH IP 4088–4092)

Jensen Wash; bed 28 (sample 90UTMI-11) Goniatites deceptus sp. nov. 4 specimens (UMNH IP 3933–3936) Goniatites sowerbyi sp. nov. 2 specimens (UMNH IP 4062–4063) Praedaraelites loeblichi (Miller & Furnish, 1940) 1 specimen (UMNH IP 4095)

194 Dieter Korn & Alan L. Titus • Goniatites Zone (middle Mississippian) ammonoids, Nevada and Utah

Jensen Wash; bed 28 (sample 97UTMI-15) Girtyoceras sp. 15 specimens (UMNH IP 3202–3216) Goniatites deceptus sp. nov. 6 specimens (UMNH IP 3824–3829)

Jensen Wash; bed 28 (sample 93UTMI-27) Girtyoceras sp. 13 specimens (UMNH IP 3201–3217–3228) Goniatites deceptus sp. nov. 9 specimens (UMNH IP 3937–3944–3996) Praedaraelites loeblichi (Miller & Furnish, 1940) 1 specimen (UMNH IP 4102)

Jensen Wash; bed 28 (sample 04UTMI-1) Goniatites deceptus sp. nov. 7 specimens (UMNH IP 3838–3844) Goniatites sp. 10 specimens (UMNH IP 4078–4087)

Material in the Museum für Naturkunde Berlin (Korn coll.):

Duckwater Hills (2007) Goniatites deceptus sp. nov. 36 specimens (MB.C.12028.1–MB.C.12028.36)

Hamilton Canyon; bed 44 (2007) Girtyoceras hamiltonense sp. nov. 16 specimens (MB.C.12005.1–MB.C.12005.16) Kazakhoceras bylundi sp. nov. 1 specimen (MB.C.12012) Goniatites eganensis sp. nov. 7 specimens (MB.C.12030.1–MB.C.12030.7) Goniatites sowerbyi sp. nov. 4 specimens (MB.C.12032.1–MB.C.12032.4) Praedaraelites loeblichi (Miller & Furnish, 1940) 4 specimens (MB.C.12034.1–MB.C.12034.4)

Cathedral Canyon (2007) Goniatites deceptus sp. nov. 16 specimens (MB.C.12027.1–MB.C.12027.16)

Rosebud Spring (2007) Goniatites americanus Gordon, 1971 6 specimens (MB.C.12020.1–MB.C.12020.6)

Granite Mountain South; bed 17 (2005) Goniatites americanus Gordon, 1971 9 specimens (MB.C.12013.1–MB.C.12013.8–MB.C.12024)

Granite Mountain South; bed 17 (2007) Calygirtyoceras arcticum (Gordon, 1957) 2 specimens (MB.C.12002.1–MB.C.120022) Dimorphoceratidae sp. indet. 1 specimen (MB.C.12009) Kazakhoceras bylundi sp. nov. 1 specimen (MB.C.12011)

Granite Mountain South; bed 25 (2005) Goniatites americanus Gordon, 1971 59 specimens (MB.C.12014.1–MB.C.12014.59) Praedaraelites loeblichi (Miller & Furnish, 1940) 1 specimen (MB.C.12033)

Granite Mountain South; bed 25 (2007) Calygirtyoceras arcticum (Gordon, 1957) 15 specimens (MB.C.12003.1–MB.C.12003.15) Girtyoceras primum sp. nov. 66 specimens (MB.C.12004.1–MB.C.12004.66) Goniatites americanus Gordon, 1971 259 specimens (MB.C.12025.1–MB.C.12025.259)

Granite Mountain North; bed 33 (2005) Goniatites deceptus sp. nov. 16 specimens (MB.C.12026.1–MB.C.12026.16)

Granite Mountain North; bed 35 (2007) Goniatites deceptus sp. nov. 21 specimens (MB.C.12029.1–MB.C.12029.21)

Foote Range (2010) Goniatites deceptus sp. nov. 3 specimens (MB.C.12039.1–MB.C.12039.3)

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Middle Confusion Range 1; bed 6 (2005) Entogonites borealis Gordon, 1957 1 specimen (MB.C.11999) Calygirtyoceras confusionense Gordon, 1957 1 specimen (MB.C.12000) Dimorphoceras rileyi sp. nov. 3 specimens (MB.C.12007.1–MB.C.12005.3) Goniatites americanus Gordon, 1971 5 specimens (MB.C.12015.1–MB.C.12015.5)

Middle Confusion Range 1; bed 8 (2005) Goniatites americanus Gordon, 1971 13 specimens (MB.C.12016.1–MB.C.12016.13)

Middle Confusion Range 1; bed 8 (2007) Goniatites americanus Gordon, 1971 5 specimens (MB.C.12021.1–MB.C.12021.5)

Middle Confusion Range 1; bed 12 (2005) Goniatites americanus Gordon, 1971 6 specimens (MB.C.12017.1–MB.C.12017.6)

Middle Confusion Range 1; bed 12 (2007) Goniatites americanus Gordon, 1971 12 specimens (MB.C.12022.1–MB.C.12022.12)

Middle Confusion Range 2; bed 9 (2005) Calygirtyoceras confusionense Gordon, 1957 2 specimens (MB.C.12001.1–MB.C.12001.2) Dimorphoceras rileyi sp. nov. 1 specimen (MB.C.12008) Goniatites americanus Gordon, 1971 5 specimens (MB.C.12018.1–MB.C.12018.5)

Middle Confusion Range 3; bed 10 (2005) Goniatites americanus Gordon, 1971 7 specimens (MB.C.12019.1–MB.C.12019.7)

Conger Mountain East; bed 14 (2010) Entogonites acus sp. nov. 1 specimen (MB.C.12035) Goniatites americanus Gordon, 1971 5 specimens (MB.C.12036.1–MB.C.12036.5)

Conger Mountain East; bed 20 (2010) Girtyoceras hamiltonense sp. nov. 2 specimens (MB.C.12037.1. MB.C.12037.2) Goniatites sowerbyi sp. nov. 2 specimens (MB.C.12038.1. MB.C.12038.2)

South Burbank Hills; bed 8 (2007) Bollandoceras sp. 2 specimens (MB.C.11998.1–MB.C.11998.2) Goniatites americanus Gordon, 1971 2 specimens (MB.C.12023.1–MB.C.12023.2)

South Burbank Hills; bed 26 (2007) Girtyoceras hamiltonense sp. nov. 10 specimens (MB.C.12006.1–MB.C.12005.10) Metadimorphoceras richardsi sp. nov. 4 specimens (MB.C.12010.1–MB.C.12010.4) Goniatites eganensis sp. nov. 4 specimens (MB.C.12031.1–MB.C.12031.4)

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